BAEL-7514: Get first n characters in a String in Java (#15817)

core-java-modules/core-java-string-operations-8/pom.xml

@@ -12,13 +12,18 @@
         <artifactId>core-java-modules</artifactId>
         <version>0.0.1-SNAPSHOT</version>
     </parent>
+
     <dependencies>
         <dependency>
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
             <version>${apache.commons.lang3.version}</version>
         </dependency>
-
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>${guava.version}</version>
+        </dependency>
     </dependencies>
 
     <build>
@@ -38,6 +43,7 @@
         <maven.compiler.source>11</maven.compiler.source>
         <maven.compiler.target>11</maven.compiler.target>
         <apache.commons.lang3.version>3.14.0</apache.commons.lang3.version>
+        <guava.version>33.0.0-jre</guava.version>
     </properties>
 
 </project>

core-java-modules/core-java-string-operations-8/src/test/java/com/baeldung/firstnchars/FirstNCharactersUnitTest.java

@@ -0,0 +1,58 @@
+package com.baeldung.firstnchars;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.jupiter.api.Test;
+
+import com.google.common.base.Ascii;
+
+class FirstNCharactersUnitTest {
+
+    @Test
+    void givenString_whenUsingSubstringMethod_thenGetFirstChars() {
+        String givenInput = "Hello Baeldung Readers";
+
+        assertEquals("He", givenInput.substring(0, 2));
+    }
+
+    @Test
+    void givenString_whenUsingSubSequenceMethod_thenGetFirstChars() {
+        String givenInput = "Welcome";
+
+        assertEquals("Wel", givenInput.subSequence(0, 3));
+    }
+
+    @Test
+    void givenString_whenUsingStreamApi_thenGetFirstChars() {
+        String givenInput = "The world is beautiful";
+        String result = givenInput.chars()
+          .limit(3)
+          .collect(StringBuilder::new, StringBuilder::appendCodePoint, StringBuilder::append)
+          .toString();
+
+        assertEquals("The", result);
+    }
+
+    @Test
+    void givenString_whenUsingStringUtilsSubstringMethod_thenGetFirstChars() {
+        String givenInput = "Baeldung";
+
+        assertEquals("Baeld", StringUtils.substring(givenInput, 0, 5));
+    }
+
+    @Test
+    void givenString_whenUsingStringUtilsLeftMethod_thenGetFirstChars() {
+        String givenInput = "kindness always wins";
+
+        assertEquals("kind", StringUtils.left(givenInput, 4));
+    }
+
+    @Test
+    void givenString_whenUsingGuavaTruncateMethod_thenGetFirstChars() {
+        String givenInput = "Tamassint";
+
+        assertEquals("Tama", Ascii.truncate(givenInput, 4, ""));
+    }
+
+}