diff --git a/core-java-modules/core-java-12/pom.xml b/core-java-modules/core-java-12/pom.xml
index ba6dfc62bc..8165549d8c 100644
--- a/core-java-modules/core-java-12/pom.xml
+++ b/core-java-modules/core-java-12/pom.xml
@@ -8,9 +8,9 @@
     <packaging>jar</packaging>
 
     <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
     </parent>
 
     <dependencies>
@@ -21,30 +21,8 @@
         </dependency>
     </dependencies>
 
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <version>${maven-compiler-plugin.version}</version>
-                <configuration>
-                    <source>${maven.compiler.source.version}</source>
-                    <target>${maven.compiler.target.version}</target>
-                    <compilerArgs>--enable-preview</compilerArgs>
-                </configuration>
-            </plugin>
-            <plugin>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <configuration>
-                    <argLine>--enable-preview</argLine>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
     <properties>
-        <maven.compiler.source.version>12</maven.compiler.source.version>
-        <maven.compiler.target.version>12</maven.compiler.target.version>
+        <java.version>17</java.version>
     </properties>
 
 </project>
\ No newline at end of file
diff --git a/core-java-modules/core-java-12/src/test/java/com/baeldung/switchExpression/SwitchUnitTest.java b/core-java-modules/core-java-12/src/test/java/com/baeldung/switchExpression/SwitchUnitTest.java
index 708e416090..994c6d9a73 100644
--- a/core-java-modules/core-java-12/src/test/java/com/baeldung/switchExpression/SwitchUnitTest.java
+++ b/core-java-modules/core-java-12/src/test/java/com/baeldung/switchExpression/SwitchUnitTest.java
@@ -19,19 +19,6 @@ public class SwitchUnitTest {
         Assert.assertEquals(value, 2);
     }
 
-    @Test
-    public void switchLocalVariable(){
-        var month = Month.AUG;
-        int i = switch (month){
-            case JAN,JUN, JUL -> 3;
-            case FEB,SEP, OCT, NOV, DEC -> 1;
-            case MAR,MAY, APR, AUG -> {
-                int j = month.toString().length() * 4;
-                break j;
-            }
-        };
-        Assert.assertEquals(12, i);
-    }
 
     enum Month {JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC}
 }
diff --git a/core-java-modules/core-java-13/pom.xml b/core-java-modules/core-java-13/pom.xml
index 11d6ee7007..52cf227583 100644
--- a/core-java-modules/core-java-13/pom.xml
+++ b/core-java-modules/core-java-13/pom.xml
@@ -8,39 +8,13 @@
     <packaging>jar</packaging>
 
     <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
     </parent>
 
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <version>${maven-compiler-plugin.version}</version>
-                <configuration>
-                    <source>${maven.compiler.source.version}</source>
-                    <target>${maven.compiler.target.version}</target>
-                    <release>13</release>
-                    <compilerArgs>--enable-preview</compilerArgs>
-                </configuration>
-            </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${surefire.plugin.version}</version>
-                <configuration>
-                    <argLine>--enable-preview</argLine>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
     <properties>
-        <maven.compiler.source.version>13</maven.compiler.source.version>
-        <maven.compiler.target.version>13</maven.compiler.target.version>
-        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
+        <java.version>17</java.version>
     </properties>
 
 </project>
\ No newline at end of file
diff --git a/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/SwitchExpressionsWithYieldUnitTest.java b/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/SwitchExpressionsWithYieldUnitTest.java
index be1fcfd167..3d3f319218 100644
--- a/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/SwitchExpressionsWithYieldUnitTest.java
+++ b/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/SwitchExpressionsWithYieldUnitTest.java
@@ -7,7 +7,6 @@ import org.junit.Test;
 public class SwitchExpressionsWithYieldUnitTest {
 
     @Test
-    @SuppressWarnings("preview")
     public void whenSwitchingOnOperationSquareMe_thenWillReturnSquare() {
         var me = 4;
         var operation = "squareMe";
diff --git a/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/TextBlocksUnitTest.java b/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/TextBlocksUnitTest.java
index 1f8ddcbfb4..e028e5f02c 100644
--- a/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/TextBlocksUnitTest.java
+++ b/core-java-modules/core-java-13/src/test/java/com/baeldung/newfeatures/TextBlocksUnitTest.java
@@ -8,7 +8,6 @@ public class TextBlocksUnitTest {
 
     private static final String JSON_STRING = "{\r\n" + "\"name\" : \"Baeldung\",\r\n" + "\"website\" : \"https://www.%s.com/\"\r\n" + "}";
 
-    @SuppressWarnings("preview")
     private static final String TEXT_BLOCK_JSON = """
             {
             "name" : "Baeldung",
@@ -25,7 +24,6 @@ public class TextBlocksUnitTest {
 
     }
 
-    @SuppressWarnings("removal")
     @Test
     public void whenTextBlocks_thenFormattedWorksAsFormat() {
         assertThat(TEXT_BLOCK_JSON.formatted("baeldung")
diff --git a/core-java-modules/core-java-13/src/test/java/com/baeldung/switchExpression/SwitchExpressionsUnitTest.java b/core-java-modules/core-java-13/src/test/java/com/baeldung/switchExpression/SwitchExpressionsUnitTest.java
index bb9250f000..04aea79a67 100644
--- a/core-java-modules/core-java-13/src/test/java/com/baeldung/switchExpression/SwitchExpressionsUnitTest.java
+++ b/core-java-modules/core-java-13/src/test/java/com/baeldung/switchExpression/SwitchExpressionsUnitTest.java
@@ -13,7 +13,6 @@ import org.junit.Test;
 public class SwitchExpressionsUnitTest {
 
   @Test
-  @SuppressWarnings ("preview")
   public void whenSwitchingOverMonthJune_thenWillReturn3() {
 
     var month = JUNE;
@@ -29,7 +28,6 @@ public class SwitchExpressionsUnitTest {
   }
 
   @Test
-  @SuppressWarnings ("preview")
   public void whenSwitchingOverMonthAugust_thenWillReturn24() {
     var month = AUGUST;
 
@@ -47,7 +45,6 @@ public class SwitchExpressionsUnitTest {
   }
 
   @Test
-  @SuppressWarnings ("preview")
   public void whenSwitchingOverMonthJanuary_thenWillReturn3() {
 
     Function<Month, Integer> func = (month) -> {
@@ -61,7 +58,6 @@ public class SwitchExpressionsUnitTest {
   }
 
   @Test
-  @SuppressWarnings ("preview")
   public void whenSwitchingOverMonthAugust_thenWillReturn2() {
     var month = AUGUST;
 
diff --git a/core-java-modules/core-java-15/pom.xml b/core-java-modules/core-java-15/pom.xml
index 3ac45d26ba..3996c69fa4 100644
--- a/core-java-modules/core-java-15/pom.xml
+++ b/core-java-modules/core-java-15/pom.xml
@@ -8,10 +8,9 @@
     <packaging>jar</packaging>
 
     <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-modules</artifactId>
-        <version>1.0.0-SNAPSHOT</version>
-        <relativePath>../../pom.xml</relativePath>
+        <groupId>com.baeldung.core-java-modules</groupId>
+        <artifactId>core-java-modules</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
     </parent>
 
     <dependencies>
@@ -27,33 +26,8 @@
         </dependency>
     </dependencies>
 
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-compiler-plugin</artifactId>
-                <version>${maven-compiler-plugin.version}</version>
-                <configuration>
-                    <release>${maven.compiler.release}</release>
-                    <compilerArgs>--enable-preview</compilerArgs>
-                    <source>14</source>
-                    <target>14</target>
-                </configuration>
-            </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-surefire-plugin</artifactId>
-                <version>${surefire.plugin.version}</version>
-                <configuration>
-                    <argLine>--enable-preview</argLine>
-                </configuration>
-            </plugin>
-        </plugins>
-    </build>
-
     <properties>
-        <maven.compiler.release>15</maven.compiler.release>
-        <surefire.plugin.version>3.0.0-M3</surefire.plugin.version>
+        <java.version>17</java.version>
     </properties>
 
 </project>
\ No newline at end of file
diff --git a/core-java-modules/pom.xml b/core-java-modules/pom.xml
index 5cae60bc2a..8cfd67aed3 100644
--- a/core-java-modules/pom.xml
+++ b/core-java-modules/pom.xml
@@ -34,6 +34,9 @@
         <module>core-java-11</module>
         <module>core-java-11-2</module>
         <module>core-java-11-3</module>
+        <module>core-java-12</module>
+        <module>core-java-13</module>
+        <module>core-java-15</module>
         <module>core-java-collections-array-list</module>
         <module>core-java-collections-array-list-2</module>
         <module>core-java-collections-list-4</module>
diff --git a/pom.xml b/pom.xml
index e3a94e7223..91e0c54784 100644
--- a/pom.xml
+++ b/pom.xml
@@ -770,10 +770,7 @@
 
                 <module>core-java-modules</module>
                 <!-- <module>core-java-modules/core-java-9-new-features</module> --> <!-- uses preview features, to be decided how to handle -->
-                <!-- <module>core-java-modules/core-java-12</module> --> <!-- uses preview features, to be decided how to handle -->
-                <!-- <module>core-java-modules/core-java-13</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-14</module> --> <!-- uses preview features, to be decided how to handle -->
-                <!-- <module>core-java-modules/core-java-15</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-16</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-17</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-19</module> --> <!-- uses preview features, to be decided how to handle -->
@@ -1051,10 +1048,7 @@
                 <module>core-java-modules</module>
                 <module>gcp-firebase</module>
                 <!-- <module>core-java-modules/core-java-9-new-features</module> --> <!-- uses preview features, to be decided how to handle -->
-                <!-- <module>core-java-modules/core-java-12</module> --> <!-- uses preview features, to be decided how to handle -->
-                <!-- <module>core-java-modules/core-java-13</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-14</module> --> <!-- uses preview features, to be decided how to handle -->
-                <!-- <module>core-java-modules/core-java-15</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-16</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-17</module> --> <!-- uses preview features, to be decided how to handle -->
                 <!-- <module>core-java-modules/core-java-19</module> --> <!-- uses preview features, to be decided how to handle -->