[JAVA] use contains function when checking whether JAVA Java string is included

When checking for Java string inclusion ex) String str = "contains test"; System.out.println( str.contains("contains") ); // true System.out.println( str.contains("what") ); // false System.out.println( str.contains("TEST") ); // false System.out.println( str.contains("test") ); // true 😀 Thank you!! 감사합니다!!