added example code for BAEL-2366 (#5730)

core-java/src/test/java/com/baeldung/string/StringReplaceAndRemoveUnitTest.java

@@ -0,0 +1,83 @@
+package com.baeldung.string;
+
+
+import org.apache.commons.lang3.StringUtils;
+import org.junit.Test;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+public class StringReplaceAndRemoveUnitTest {
+
+
+    @Test
+    public void givenTestStrings_whenReplace_thenProcessedString() {
+
+        String master = "Hello World Baeldung!";
+        String target = "Baeldung";
+        String replacement = "Java";
+        String processed = master.replace(target, replacement);
+        assertTrue(processed.contains(replacement));
+        assertFalse(processed.contains(target));
+
+    }
+
+    @Test
+    public void givenTestStrings_whenReplaceAll_thenProcessedString() {
+
+        String master2 = "Welcome to Baeldung, Hello World Baeldung";
+        String regexTarget= "(Baeldung)$";
+        String replacement = "Java";
+        String processed2 = master2.replaceAll(regexTarget, replacement);
+        assertTrue(processed2.endsWith("Java"));
+
+    }
+
+    @Test
+    public void givenTestStrings_whenStringBuilderMethods_thenProcessedString() {
+
+        String master = "Hello World Baeldung!";
+        String target = "Baeldung";
+        String replacement = "Java";
+
+        int startIndex = master.indexOf(target);
+        int stopIndex = startIndex + target.length();
+
+        StringBuilder builder = new StringBuilder(master);
+
+
+        builder.delete(startIndex, stopIndex);
+        assertFalse(builder.toString().contains(target));
+
+
+        builder.replace(startIndex, stopIndex, replacement);
+        assertTrue(builder.toString().contains(replacement));
+
+
+    }
+
+
+    @Test
+    public void givenTestStrings_whenStringUtilsMethods_thenProcessedStrings() {
+
+        String master = "Hello World Baeldung!";
+        String target = "Baeldung";
+        String replacement = "Java";
+
+        String processed = StringUtils.replace(master, target, replacement);
+        assertTrue(processed.contains(replacement));
+
+        String master2 = "Hello World Baeldung!";
+        String target2 = "baeldung";
+        String processed2 = StringUtils.replaceIgnoreCase(master2, target2, replacement);
+        assertFalse(processed2.contains(target));
+
+    }
+
+
+
+
+
+
+
+}