why do these statements give different answers?
String s1="hello world";
String s2="hello world";
System.out.println(s1.equals(s2));//true
System.out.println(s1 == s2);//true
2nd case;
String s1=new String("hello world");
String s2=new String("hello world");
System.out.println(s1.equals(s2));//true
System.out.println(s1 == s2);//false
s1.equals(s2) compares the content of the two strings whereas s1 == s2 compares the objects' references.
Since both s1 and s2 are two different instances of the String class, their references are not equal. The == operator behaves this way for all Objects.
== just compares two references - i.e. it tests whether the two operands refer to the same object. s1 and s2 are two different objects so that's why the comparison is false.
