diff --git a/core-java/src/main/java/com/baeldung/system/DetectOS.java b/core-java/src/main/java/com/baeldung/system/DetectOS.java
new file mode 100644
index 0000000000..2d605fe49f
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/system/DetectOS.java
@@ -0,0 +1,18 @@
+package com.baeldung.system;
+
+import org.apache.commons.lang3.SystemUtils;
+
+public class DetectOS {
+
+    public String getOperatingSystem() {
+        String os = System.getProperty("os.name");
+        System.out.println("Using System Property: " + os);
+        return os;
+    }
+
+    public String getOperatingSystemSystemUtils() {
+        String os = SystemUtils.OS_NAME;
+        System.out.println("Using SystemUtils: " + os);
+        return os;
+    }
+}
diff --git a/core-java/src/test/java/com/baeldung/system/WhenDetectingOSTest.java b/core-java/src/test/java/com/baeldung/system/WhenDetectingOSTest.java
new file mode 100644
index 0000000000..77901f6524
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/system/WhenDetectingOSTest.java
@@ -0,0 +1,25 @@
+package com.baeldung.system;
+
+import org.junit.Assert;
+import org.junit.Ignore;
+import org.junit.Test;
+
+@Ignore
+public class WhenDetectingOSTest {
+
+    private DetectOS os = new DetectOS();
+
+    @Test
+    public void whenUsingSystemProperty_shouldReturnOS() {
+        String expected = "Windows 10";
+        String actual = os.getOperatingSystem();
+        Assert.assertEquals(expected, actual);
+    }
+
+    @Test
+    public void whenUsingSystemUtils_shouldReturnOS() {
+        String expected = "Windows 10";
+        String actual = os.getOperatingSystemSystemUtils();
+        Assert.assertEquals(expected, actual);
+    }
+}
diff --git a/guava/pom.xml b/guava/pom.xml
index 4afb4da301..aa162b7d1b 100644
--- a/guava/pom.xml
+++ b/guava/pom.xml
@@ -43,6 +43,14 @@
             <version>${assertj.version}</version>
             <scope>test</scope>
         </dependency>
+        
+        <dependency>
+            <groupId>org.hamcrest</groupId>
+            <artifactId>java-hamcrest</artifactId>
+            <version>2.0.0.0</version>
+            <scope>test</scope>
+        </dependency>
+        
     </dependencies>
 
     <build>
diff --git a/guava/src/test/java/org/baeldung/hamcrest/HamcrestFileUnitTest.java b/guava/src/test/java/org/baeldung/hamcrest/HamcrestFileUnitTest.java
new file mode 100644
index 0000000000..652e315651
--- /dev/null
+++ b/guava/src/test/java/org/baeldung/hamcrest/HamcrestFileUnitTest.java
@@ -0,0 +1,64 @@
+package org.baeldung.hamcrest;
+
+import static org.hamcrest.core.StringContains.containsString;
+import static org.hamcrest.io.FileMatchers.aFileNamed;
+import static org.hamcrest.io.FileMatchers.aFileWithAbsolutePath;
+import static org.hamcrest.io.FileMatchers.aFileWithCanonicalPath;
+import static org.hamcrest.io.FileMatchers.aFileWithSize;
+import static org.hamcrest.io.FileMatchers.aReadableFile;
+import static org.hamcrest.io.FileMatchers.aWritableFile;
+import static org.hamcrest.io.FileMatchers.anExistingDirectory;
+import static org.hamcrest.io.FileMatchers.anExistingFile;
+import static org.hamcrest.io.FileMatchers.anExistingFileOrDirectory;
+import static org.hamcrest.number.OrderingComparison.greaterThan;
+import static org.hamcrest.text.IsEqualIgnoringCase.equalToIgnoringCase;
+import static org.junit.Assert.assertThat;
+
+import java.io.File;
+
+import org.junit.Test;
+
+public class HamcrestFileUnitTest {
+
+    @Test
+    public final void whenVerifyingFileName_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+
+        assertThat(file, aFileNamed(equalToIgnoringCase("test1.in")));
+    }
+
+    @Test
+    public final void whenVerifyingFileOrDirExist_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+        File dir = new File("src/test/resources");
+        
+        assertThat(file, anExistingFile());
+        assertThat(dir, anExistingDirectory());
+        assertThat(file, anExistingFileOrDirectory());
+        assertThat(dir, anExistingFileOrDirectory());
+    }
+
+    @Test
+    public final void whenVerifyingFileIsReadableAndWritable_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+
+        assertThat(file, aReadableFile());
+        assertThat(file, aWritableFile());        
+    }
+
+    @Test
+    public final void whenVerifyingFileSize_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+
+        assertThat(file, aFileWithSize(11));
+        assertThat(file, aFileWithSize(greaterThan(1L)));;
+    }
+
+    @Test
+    public final void whenVerifyingFilePath_thenCorrect() {
+        File file = new File("src/test/resources/test1.in");
+        
+        assertThat(file, aFileWithCanonicalPath(containsString("src/test/resources")));
+        assertThat(file, aFileWithAbsolutePath(containsString("src/test/resources")));
+    }
+}
diff --git a/guava/src/test/java/org/baeldung/hamcrest/HamcrestTextUnitTest.java b/guava/src/test/java/org/baeldung/hamcrest/HamcrestTextUnitTest.java
new file mode 100644
index 0000000000..e336b1bba3
--- /dev/null
+++ b/guava/src/test/java/org/baeldung/hamcrest/HamcrestTextUnitTest.java
@@ -0,0 +1,97 @@
+package org.baeldung.hamcrest;
+
+import static org.hamcrest.core.StringContains.containsString;
+import static org.hamcrest.core.StringContains.containsStringIgnoringCase;
+import static org.hamcrest.core.StringEndsWith.endsWith;
+import static org.hamcrest.core.StringEndsWith.endsWithIgnoringCase;
+import static org.hamcrest.core.StringStartsWith.startsWith;
+import static org.hamcrest.core.StringStartsWith.startsWithIgnoringCase;
+import static org.hamcrest.text.IsBlankString.blankOrNullString;
+import static org.hamcrest.text.IsBlankString.blankString;
+import static org.hamcrest.text.IsEmptyString.emptyOrNullString;
+import static org.hamcrest.text.IsEmptyString.emptyString;
+import static org.hamcrest.text.IsEqualIgnoringCase.equalToIgnoringCase;
+import static org.hamcrest.text.IsEqualIgnoringWhiteSpace.equalToIgnoringWhiteSpace;
+import static org.hamcrest.text.MatchesPattern.matchesPattern;
+import static org.hamcrest.text.StringContainsInOrder.stringContainsInOrder;
+import static org.junit.Assert.assertThat;
+
+import org.junit.Test;
+
+public class HamcrestTextUnitTest {
+    
+    @Test
+    public final void whenTwoStringsAreEqual_thenCorrect() {
+        String first = "hello";
+        String second = "Hello";
+        
+        assertThat(first, equalToIgnoringCase(second));
+    }
+
+    @Test
+    public final void whenTwoStringsAreEqualWithWhiteSpace_thenCorrect() {
+        String first = "hello";
+        String second = "   Hello   ";
+        
+        assertThat(first, equalToIgnoringWhiteSpace(second));
+    }
+
+    @Test
+    public final void whenStringIsBlank_thenCorrect() {
+        String first = "  ";
+        String second = null;
+
+        assertThat(first, blankString());
+        assertThat(first, blankOrNullString());
+        assertThat(second, blankOrNullString());
+    }
+
+    @Test
+    public final void whenStringIsEmpty_thenCorrect() {
+        String first = "";
+        String second = null;
+
+        assertThat(first, emptyString());
+        assertThat(first, emptyOrNullString());
+        assertThat(second, emptyOrNullString());
+    }
+
+    @Test
+    public final void whenStringMatchPattern_thenCorrect() {
+        String first = "hello";
+
+        assertThat(first, matchesPattern("[a-z]+"));
+    }
+
+    @Test
+    public final void whenVerifyStringContains_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, containsString("lo"));
+        assertThat(first, containsStringIgnoringCase("EL"));
+    }
+    
+    @Test
+    public final void whenVerifyStringContainsInOrder_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, stringContainsInOrder("e","l","o"));
+    }
+    
+    @Test
+    public final void whenVerifyStringStartsWith_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, startsWith("he"));
+        assertThat(first, startsWithIgnoringCase("HEL"));
+    }
+    
+    @Test
+    public final void whenVerifyStringEndsWith_thenCorrect() {
+        String first = "hello";
+    
+        assertThat(first, endsWith("lo"));
+        assertThat(first, endsWithIgnoringCase("LO"));
+    }
+    
+}