Added string methods

src/main/java/org/apache/commons/lang3/StringUtils.java

@@ -9245,5 +9245,25 @@ public static int[] toCodePoints(CharSequence str) {
             index += Character.charCount(result[i]);
         }
         return result;
+    }    
+
+    /**
+     * <p>Finds index of all the occurences of given search key found in source string.
+     * </p>
+     * @param source
+     * @param searchKey
+     * @return list of integer of indexes.
+     */
+    public static List<Integer> indexesOf(final CharSequence source, final Character searchKey) {
+    	if(isEmpty(source) || searchKey == CharUtils.NUL ) {
+    	    return null;
+    	}
+    	List<Integer> indexList = new ArrayList<>();
+    	for(int i = 0 ; i < source.length() ; i++) {
+    	    if(searchKey.equals(source.charAt(i))) {
+    		    indexList.add(i);
+    	    }
+    	}
+    	return indexList;    	
     }
 }

src/test/java/org/apache/commons/lang3/StringUtilsTest.java

@@ -19,6 +19,7 @@
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertSame;
@@ -3229,6 +3230,14 @@ public void testToCodePoints() throws Exception {
         assertNull(StringUtils.toCodePoints(null));
         assertArrayEquals(ArrayUtils.EMPTY_INT_ARRAY, StringUtils.toCodePoints(""));
     }
+
+    @Test
+    public void testIndexesOf() throws Exception {
+    	assertEquals(null, 3, StringUtils.indexesOf("anagram", 'a').size());
+    	assertEquals(null, 2, StringUtils.indexesOf("Reader", 'e').size());
+    	assertNull(StringUtils.indexesOf("people", null));
+    	assertNotEquals(null, 2, StringUtils.indexesOf("Automatic", 'o').size());
+    }
 
     @Test
     public void testGetDigits() {