== vs equals in java

/**
 *
 * TODO Description go here.
 *
 * @author <a href="mailto:varra@outlook.com">Rajakrishna V. Reddy</a>
 * @version 1.0
 *
 */
public class StringManual
{
   
    /**
     * The main method.
     *
     * @param args
     *            the arguments
     */
    public static void main(String[] args)
    {
        String s1 = "foo"; //Creates a string in String constant pool rather in heap. [Happens the same for all strings created as ""]
        String s2 = "foo"; // String constant pool will not create a new string as there is already a string with the same content S1, so s2 points to the s1 i.e s2=s1.
       
        System.out.println(s1 == s2); // TRUE: because s2=s1, both references are same i.e s1.
        System.out.println(s1.equals(s2)); // TRUE: based on content.
       
        String s3 = new String("foo"); //Creates a string in heap. [Happens the same for all strings created as new String.]
        System.out.println(s1 == s3); // FALSE: because both references are not same i.e s1 is in constant pool and s3 is in heap.
        System.out.println(s1.equals(s3)); // TRUE: based on content.
    }
}