diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/README.adoc b/servlet/spring-boot/java/oauth2/resource-server/opaque/README.adoc
new file mode 100644
index 0000000..fc6add9
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/README.adoc
@@ -0,0 +1,114 @@
+= OAuth 2.0 Resource Server Sample
+
+This sample demonstrates integrating Resource Server with a mock Authorization Server, though it can be modified to integrate
+with your favorite Authorization Server.
+
+With it, you can run the integration tests or run the application as a stand-alone service to explore how you can
+secure your own service with OAuth 2.0 Opaque Bearer Tokens using Spring Security.
+
+== 1. Running the tests
+
+To run the tests, do:
+
+```bash
+./gradlew integrationTest
+```
+
+Or import the project into your IDE and run `OAuth2ResourceServerApplicationTests` from there.
+
+=== What is it doing?
+
+By default, the tests are pointing at a mock Authorization Server instance.
+
+The tests are configured with a set of hard-coded tokens originally obtained from the mock Authorization Server,
+and each makes a query to the Resource Server with their corresponding token.
+
+The Resource Server subsquently verifies with the Authorization Server and authorizes the request, returning the phrase
+
+```bash
+Hello, subject!
+```
+
+where "subject" is the value of the `sub` field in the JWT returned by the Authorization Server.
+
+== 2. Running the app
+
+To run as a stand-alone application, do:
+
+```bash
+./gradlew bootRun
+```
+
+Or import the project into your IDE and run `OAuth2ResourceServerApplication` from there.
+
+Once it is up, you can use the following token:
+
+```bash
+export TOKEN=00ed5855-1869-47a0-b0c9-0f3ce520aee7
+```
+
+And then make this request:
+
+```bash
+curl -H "Authorization: Bearer $TOKEN" localhost:8080
+```
+
+Which will respond with the phrase:
+
+```bash
+Hello, subject!
+```
+
+where `subject` is the value of the `sub` field in the JWT returned by the Authorization Server.
+
+Or this:
+
+```bash
+export TOKEN=b43d1500-c405-4dc9-b9c9-6cfd966c34c9
+
+curl -H "Authorization: Bearer $TOKEN" localhost:8080/message
+```
+
+Will respond with:
+
+```bash
+secret message
+```
+
+== 2. Testing against other Authorization Servers
+
+_In order to use this sample, your Authorization Server must support Opaque Tokens and the Introspection Endpoint.
+
+To change the sample to point at your Authorization Server, simply find this property in the `application.yml`:
+
+```yaml
+spring:
+  security:
+    oauth2:
+      resourceserver:
+        opaque:
+          introspection-uri: ${mockwebserver.url}/introspect
+          introspection-client-id: client
+          introspection-client-secret: secret
+```
+
+And change the property to your Authorization Server's Introspection endpoint, including its client id and secret:
+
+```yaml
+spring:
+  security:
+    oauth2:
+      resourceserver:
+        opaque:
+          introspection-uri: ${mockwebserver.url}/introspect
+```
+
+And then you can run the app the same as before:
+
+```bash
+./gradlew bootRun
+```
+
+Make sure to obtain valid tokens from your Authorization Server in order to play with the sample Resource Server.
+To use the `/` endpoint, any valid token from your Authorization Server will do.
+To use the `/message` endpoint, the token should have the `message:read` scope.
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/build.gradle b/servlet/spring-boot/java/oauth2/resource-server/opaque/build.gradle
new file mode 100644
index 0000000..bbb0f92
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/build.gradle
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins {
+	id 'org.springframework.boot' version '2.2.6.RELEASE'
+	id 'io.spring.dependency-management' version '1.0.9.RELEASE'
+	id "nebula.integtest" version "7.0.9"
+	id 'java'
+}
+
+repositories {
+	mavenCentral()
+	maven { url "https://repo.spring.io/snapshot" }
+}
+
+dependencies {
+	implementation 'com.squareup.okhttp3:mockwebserver'
+	implementation 'org.springframework.boot:spring-boot-starter-oauth2-resource-server'
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+	implementation 'com.nimbusds:oauth2-oidc-sdk:7.4'
+
+	testImplementation 'org.springframework.boot:spring-boot-starter-test'
+	testImplementation 'org.springframework.security:spring-security-test'
+}
+
+tasks.withType(Test).configureEach {
+	useJUnitPlatform()
+}
\ No newline at end of file
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle.properties b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle.properties
new file mode 100644
index 0000000..7def6a0
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle.properties
@@ -0,0 +1 @@
+spring-security.version=5.4.0.BUILD-SNAPSHOT
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle/wrapper/gradle-wrapper.jar b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..f3d88b1
Binary files /dev/null and b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle/wrapper/gradle-wrapper.properties b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..a2bf131
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.2.2-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/gradlew b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradlew
new file mode 100755
index 0000000..2fe81a7
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradlew
@@ -0,0 +1,183 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/gradlew.bat b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradlew.bat
new file mode 100644
index 0000000..9109989
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/gradlew.bat
@@ -0,0 +1,103 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/settings.gradle b/servlet/spring-boot/java/oauth2/resource-server/opaque/settings.gradle
new file mode 100644
index 0000000..8b13789
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/settings.gradle
@@ -0,0 +1 @@
+
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/integTest/java/example/OAuth2ResourceServerApplicationITests.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/integTest/java/example/OAuth2ResourceServerApplicationITests.java
new file mode 100644
index 0000000..51c3027
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/integTest/java/example/OAuth2ResourceServerApplicationITests.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpHeaders;
+import org.springframework.mock.web.MockHttpServletRequest;
+import org.springframework.test.context.ActiveProfiles;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.request.RequestPostProcessor;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.header;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ * Integration tests for {@link OAuth2ResourceServerApplication}.
+ *
+ * @author Josh Cummings
+ */
+@SpringBootTest
+@AutoConfigureMockMvc
+@ActiveProfiles("test")
+public class OAuth2ResourceServerApplicationITests {
+
+	String noScopesToken = "00ed5855-1869-47a0-b0c9-0f3ce520aee7";
+
+	String messageReadToken = "b43d1500-c405-4dc9-b9c9-6cfd966c34c9";
+
+	@Autowired
+	MockMvc mvc;
+
+	@Test
+	void performWhenValidBearerTokenThenAllows() throws Exception {
+
+		// @formatter:off
+		this.mvc.perform(get("/").with(bearerToken(this.noScopesToken)))
+				.andExpect(status().isOk())
+				.andExpect(content().string(containsString("Hello, subject!")));
+		// @formatter:on
+	}
+
+	// -- tests with scopes
+
+	@Test
+	void performWhenValidBearerTokenThenScopedRequestsAlsoWork() throws Exception {
+
+		// @formatter:off
+		this.mvc.perform(get("/message").with(bearerToken(this.messageReadToken)))
+				.andExpect(status().isOk())
+				.andExpect(content().string(containsString("secret message")));
+		// @formatter:on
+	}
+
+	@Test
+	void performWhenInsufficientlyScopedBearerTokenThenDeniesScopedMethodAccess() throws Exception {
+
+		// @formatter:off
+		this.mvc.perform(get("/message").with(bearerToken(this.noScopesToken)))
+				.andExpect(status().isForbidden())
+				.andExpect(header().string(HttpHeaders.WWW_AUTHENTICATE,
+						containsString("Bearer error=\"insufficient_scope\"")));
+		// @formatter:on
+	}
+
+	private static BearerTokenRequestPostProcessor bearerToken(String token) {
+		return new BearerTokenRequestPostProcessor(token);
+	}
+
+	private static class BearerTokenRequestPostProcessor implements RequestPostProcessor {
+
+		private String token;
+
+		BearerTokenRequestPostProcessor(String token) {
+			this.token = token;
+		}
+
+		@Override
+		public MockHttpServletRequest postProcessRequest(MockHttpServletRequest request) {
+			request.addHeader("Authorization", "Bearer " + this.token);
+			return request;
+		}
+
+	}
+
+}
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerApplication.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerApplication.java
new file mode 100644
index 0000000..9293938
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerApplication.java
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * OAuth2 Resource Application.
+ *
+ * @author Josh Cummings
+ */
+@SpringBootApplication
+public class OAuth2ResourceServerApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(OAuth2ResourceServerApplication.class, args);
+	}
+
+}
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerController.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerController.java
new file mode 100644
index 0000000..64afe3f
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerController.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import org.springframework.security.core.annotation.AuthenticationPrincipal;
+import org.springframework.security.oauth2.core.OAuth2AuthenticatedPrincipal;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Controller demonstrating OAuth.
+ *
+ * @author Josh Cummings
+ */
+@RestController
+public class OAuth2ResourceServerController {
+
+	@GetMapping("/")
+	public String index(@AuthenticationPrincipal OAuth2AuthenticatedPrincipal principal) {
+		return String.format("Hello, %s!", (String) principal.getAttribute("sub"));
+	}
+
+	@GetMapping("/message")
+	public String message() {
+		return "secret message";
+	}
+
+	@PostMapping("/message")
+	public String createMessage(@RequestBody String message) {
+		return String.format("Message was created. Content: %s", message);
+	}
+
+}
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerSecurityConfiguration.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerSecurityConfiguration.java
new file mode 100644
index 0000000..a3cfc65
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/example/OAuth2ResourceServerSecurityConfiguration.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.HttpMethod;
+import org.springframework.security.config.annotation.web.builders.HttpSecurity;
+import org.springframework.security.config.annotation.web.configuration.EnableWebSecurity;
+import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
+
+/**
+ * OAuth2 Security Configuration.
+ *
+ * @author Josh Cummings
+ */
+@EnableWebSecurity
+public class OAuth2ResourceServerSecurityConfiguration extends WebSecurityConfigurerAdapter {
+
+	@Value("${spring.security.oauth2.resourceserver.opaque.introspection-uri}")
+	String introspectionUri;
+
+	@Value("${spring.security.oauth2.resourceserver.opaque.introspection-client-id}")
+	String clientId;
+
+	@Value("${spring.security.oauth2.resourceserver.opaque.introspection-client-secret}")
+	String clientSecret;
+
+	@Override
+	protected void configure(HttpSecurity http) throws Exception {
+		// @formatter:off
+		http
+			.authorizeRequests((requests) -> requests
+					.mvcMatchers(HttpMethod.GET, "/message/**").hasAuthority("SCOPE_message:read")
+					.mvcMatchers(HttpMethod.POST, "/message/**").hasAuthority("SCOPE_message:write")
+					.anyRequest().authenticated()
+			)
+			.oauth2ResourceServer((resourceServer) -> resourceServer
+					.opaqueToken((opaqueToken) -> opaqueToken
+						.introspectionUri(this.introspectionUri)
+						.introspectionClientCredentials(this.clientId, this.clientSecret)
+					)
+			);
+		// @formatter:on
+	}
+
+}
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/MockWebServerEnvironmentPostProcessor.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/MockWebServerEnvironmentPostProcessor.java
new file mode 100644
index 0000000..6b27444
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/MockWebServerEnvironmentPostProcessor.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.env;
+
+import org.springframework.beans.factory.DisposableBean;
+import org.springframework.boot.SpringApplication;
+import org.springframework.core.env.ConfigurableEnvironment;
+
+/**
+ * Add MockServerWebPropertySource to environment.
+ *
+ * @author Rob Winch
+ */
+public class MockWebServerEnvironmentPostProcessor implements EnvironmentPostProcessor, DisposableBean {
+
+	private final MockWebServerPropertySource propertySource = new MockWebServerPropertySource();
+
+	@Override
+	public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
+		environment.getPropertySources().addFirst(this.propertySource);
+	}
+
+	@Override
+	public void destroy() throws Exception {
+		this.propertySource.destroy();
+	}
+
+}
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/MockWebServerPropertySource.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/MockWebServerPropertySource.java
new file mode 100644
index 0000000..e65b1e5
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/MockWebServerPropertySource.java
@@ -0,0 +1,201 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.env;
+
+import java.io.IOException;
+import java.util.Base64;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import okhttp3.mockwebserver.Dispatcher;
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import okhttp3.mockwebserver.RecordedRequest;
+import okio.Buffer;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
+import org.springframework.beans.factory.DisposableBean;
+import org.springframework.core.env.PropertySource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+
+/**
+ * Add the resource server URL to environment.
+ *
+ * @author Rob Winch
+ */
+public class MockWebServerPropertySource extends PropertySource<MockWebServer> implements DisposableBean {
+
+	// @formatter:off
+	private static final MockResponse NO_SCOPES_RESPONSE = response(
+			"{\n" +
+					"      \"active\": true,\n" +
+					"      \"sub\": \"subject\"\n" +
+					"     }",
+			200
+	);
+	// @formatter:on
+
+	// @formatter:off
+	private static final MockResponse MESSASGE_READ_SCOPE_RESPONSE = response(
+			"{\n" +
+					"      \"active\": true,\n" +
+					"      \"scope\" : \"message:read\"," +
+					"      \"sub\": \"subject\"\n" +
+					"     }",
+			200
+	);
+	// @formatter:on
+
+	// @formatter:off
+	private static final MockResponse INACTIVE_RESPONSE = response(
+			"{\n" +
+					"      \"active\": false,\n" +
+					"     }",
+			200
+	);
+	// @formatter:on
+
+	// @formatter:off
+	private static final MockResponse BAD_REQUEST_RESPONSE = response(
+			"{ \"message\" : \"This mock authorization server requires a username and password of " +
+					"client/secret and a POST body of token=${token}\" }",
+			400
+	);
+	// @formatter:on
+
+	// @formatter:off
+	private static final MockResponse NOT_FOUND_RESPONSE = response(
+			"{ \"message\" : \"This mock authorization server responds to just one request: POST /introspect.\" }",
+			404
+	);
+	// @formatter:on
+
+	/**
+	 * Name of the random {@link PropertySource}.
+	 */
+	public static final String MOCK_WEB_SERVER_PROPERTY_SOURCE_NAME = "mockwebserver";
+
+	private static final String NAME = "mockwebserver.url";
+
+	private static final Log logger = LogFactory.getLog(MockWebServerPropertySource.class);
+
+	private boolean started;
+
+	public MockWebServerPropertySource() {
+		super(MOCK_WEB_SERVER_PROPERTY_SOURCE_NAME, new MockWebServer());
+	}
+
+	@Override
+	public Object getProperty(String name) {
+		if (!name.equals(NAME)) {
+			return null;
+		}
+		if (logger.isTraceEnabled()) {
+			logger.trace("Looking up the url for '" + name + "'");
+		}
+		String url = getUrl();
+		return url;
+	}
+
+	@Override
+	public void destroy() throws Exception {
+		getSource().shutdown();
+	}
+
+	/**
+	 * Get's the URL (e.g. "http://localhost:123456")
+	 * @return the resource URL.
+	 */
+	private String getUrl() {
+		MockWebServer mockWebServer = getSource();
+		if (!this.started) {
+			initializeMockWebServer(mockWebServer);
+		}
+		String url = mockWebServer.url("").url().toExternalForm();
+		return url.substring(0, url.length() - 1);
+	}
+
+	private void initializeMockWebServer(MockWebServer mockWebServer) {
+		Dispatcher dispatcher = new Dispatcher() {
+			@Override
+			public MockResponse dispatch(RecordedRequest request) {
+				return doDispatch(request);
+			}
+		};
+
+		mockWebServer.setDispatcher(dispatcher);
+		try {
+			mockWebServer.start();
+			this.started = true;
+		}
+		catch (IOException ex) {
+			throw new RuntimeException("Could not start " + mockWebServer, ex);
+		}
+	}
+
+	private MockResponse doDispatch(RecordedRequest request) {
+		if ("/introspect".equals(request.getPath())) {
+			// @formatter:off
+			return Optional.ofNullable(request.getHeader(HttpHeaders.AUTHORIZATION))
+					.filter((authorization) -> isAuthorized(authorization, "client", "secret"))
+					.map((authorization) -> parseBody(request.getBody()))
+					.map((parameters) -> parameters.get("token"))
+					.map((token) -> {
+						if ("00ed5855-1869-47a0-b0c9-0f3ce520aee7".equals(token)) {
+							return NO_SCOPES_RESPONSE;
+						}
+						else if ("b43d1500-c405-4dc9-b9c9-6cfd966c34c9".equals(token)) {
+							return MESSASGE_READ_SCOPE_RESPONSE;
+						}
+						else {
+							return INACTIVE_RESPONSE;
+						}
+					})
+					.orElse(BAD_REQUEST_RESPONSE);
+			// @formatter:on
+		}
+
+		return NOT_FOUND_RESPONSE;
+	}
+
+	private boolean isAuthorized(String authorization, String username, String password) {
+		String[] values = new String(Base64.getDecoder().decode(authorization.substring(6))).split(":");
+		return username.equals(values[0]) && password.equals(values[1]);
+	}
+
+	private Map<String, Object> parseBody(Buffer body) {
+		// @formatter:off
+		return Stream.of(body.readUtf8().split("&"))
+				.map((parameter) -> parameter.split("="))
+				.collect(Collectors.toMap((parts) -> parts[0], (parts) -> parts[1]));
+		// @formatter:on
+	}
+
+	private static MockResponse response(String body, int status) {
+		// @formatter:off
+		return new MockResponse()
+				.setHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
+				.setResponseCode(status)
+				.setBody(body);
+		// @formatter:on
+	}
+
+}
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/package-info.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/package-info.java
new file mode 100644
index 0000000..aa36737
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/java/org/springframework/boot/env/package-info.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * This provides integration of a {@link okhttp3.mockwebserver.MockWebServer} and the
+ * {@link org.springframework.core.env.Environment}.
+ *
+ * @author Rob Winch
+ */
+package org.springframework.boot.env;
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/resources/META-INF/spring.factories b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/resources/META-INF/spring.factories
new file mode 100644
index 0000000..37b447c
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/resources/META-INF/spring.factories
@@ -0,0 +1 @@
+org.springframework.boot.env.EnvironmentPostProcessor=org.springframework.boot.env.MockWebServerEnvironmentPostProcessor
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/resources/application.yml b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/resources/application.yml
new file mode 100644
index 0000000..a7dcfea
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/main/resources/application.yml
@@ -0,0 +1,8 @@
+spring:
+  security:
+    oauth2:
+      resourceserver:
+        opaque:
+          introspection-uri: ${mockwebserver.url}/introspect
+          introspection-client-id: client
+          introspection-client-secret: secret
diff --git a/servlet/spring-boot/java/oauth2/resource-server/opaque/src/test/java/example/OAuth2ResourceServerControllerTests.java b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/test/java/example/OAuth2ResourceServerControllerTests.java
new file mode 100644
index 0000000..037932e
--- /dev/null
+++ b/servlet/spring-boot/java/oauth2/resource-server/opaque/src/test/java/example/OAuth2ResourceServerControllerTests.java
@@ -0,0 +1,104 @@
+/*
+ * Copyright 2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package example;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.security.core.authority.SimpleGrantedAuthority;
+import org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors;
+import org.springframework.test.web.servlet.MockMvc;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.jwt;
+import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.opaqueToken;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+/**
+ * @author Josh Cummings
+ * @since 5.3
+ */
+@WebMvcTest(OAuth2ResourceServerController.class)
+public class OAuth2ResourceServerControllerTests {
+
+	@Autowired
+	MockMvc mvc;
+
+	@Test
+	void indexGreetsAuthenticatedUser() throws Exception {
+		// @formatter:off
+		SecurityMockMvcRequestPostProcessors.OpaqueTokenRequestPostProcessor token = opaqueToken()
+				.attributes((a) -> a.put("sub", "ch4mpy"));
+		this.mvc.perform(get("/").with(token))
+				.andExpect(content().string(is("Hello, ch4mpy!")));
+		// @formatter:on
+	}
+
+	@Test
+	void messageCanBeReadWithScopeMessageReadAuthority() throws Exception {
+		// @formatter:off
+		SecurityMockMvcRequestPostProcessors.OpaqueTokenRequestPostProcessor token = opaqueToken()
+				.attributes((a) -> a.put("scope", "message:read"));
+		this.mvc.perform(get("/message").with(token))
+				.andExpect(content().string(is("secret message")));
+
+		this.mvc.perform(get("/message")
+				.with(jwt().authorities(new SimpleGrantedAuthority(("SCOPE_message:read")))))
+				.andExpect(content().string(is("secret message")));
+		// @formatter:on
+	}
+
+	@Test
+	void messageCanNotBeReadWithoutScopeMessageReadAuthority() throws Exception {
+		// @formatter:off
+		this.mvc.perform(get("/message").with(opaqueToken()))
+				.andExpect(status().isForbidden());
+		// @formatter:on
+	}
+
+	@Test
+	void messageCanNotBeCreatedWithoutAnyScope() throws Exception {
+		// @formatter:off
+		this.mvc.perform(post("/message")
+				.content("Hello message")
+				.with(opaqueToken()))
+				.andExpect(status().isForbidden());
+		// @formatter:on
+	}
+
+	@Test
+	void messageCanNotBeCreatedWithScopeMessageReadAuthority() throws Exception {
+		this.mvc.perform(post("/message").content("Hello message")
+				.with(opaqueToken().authorities(new SimpleGrantedAuthority("SCOPE_message:read"))))
+				.andExpect(status().isForbidden());
+	}
+
+	@Test
+	void messageCanBeCreatedWithScopeMessageWriteAuthority() throws Exception {
+		// @formatter:off
+		this.mvc.perform(post("/message")
+				.content("Hello message")
+				.with(opaqueToken().authorities(new SimpleGrantedAuthority("SCOPE_message:write"))))
+				.andExpect(status().isOk())
+				.andExpect(content().string(is("Message was created. Content: Hello message")));
+		// @formatter:on
+	}
+
+}
diff --git a/settings.gradle b/settings.gradle
index 5406495..4d78ba3 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -32,6 +32,6 @@ include ":servlet:spring-boot:java:hello-security-explicit"
 include ":servlet:spring-boot:java:oauth2:login"
 include ":servlet:spring-boot:java:oauth2:resource-server:hello-security"
 include ":servlet:spring-boot:java:oauth2:resource-server:jwe"
+include ":servlet:spring-boot:java:oauth2:resource-server:opaque"
 include ":servlet:spring-boot:java:oauth2:webclient"
 include ":servlet:spring-boot:kotlin:hello-security"
-