StringBuffer Question

[Kenneth Ho]

Question 53. in Abhilash Java Quiz
I would like to know whether StringBuffer can be used to compare string. I complied and run the foll codes and it shows nothing.

    Read the code below carefully. 
  
    public class TestClass 
    { 
        public static void main(String Args[]) 
        { 
            StringBuffer sb1 = new StringBuffer("String"); 
            StringBuffer sb2 = new StringBuffer("String"); 
            if(sb1.equals(sb2)) 
            { 
                System.out.println("Equal!");//lots of code 
            } 
         } 
    }

[Johannes de Jong]

Originally posted by Frank Carver:
The two StringBuffers don't come out as equal, because StringBuffer just uses the "default" implementation of equals(), which does the same as '==' and directly compares the object references. The two StringBuffers are different objects with different references, so they come out as non-equal.

And

Originally posted by Hari Gangadharan:
I really love this question! The StringBuffer *does* not override Object's "equals" method whereas String do. Hence when you invoke s1.equals(s2), the equals method of Object is invoked. The equals method of Object just does a shallow compare (which essentially is s1 == s2) and returns false!
Hope this helps --

[This message has been edited by Johannes de Jong (edited April 06, 2001).]

[Jim Yingst]

The JavaRanch forum in intended for discussion of this web site, not questions about Java itself. That's what all the other forums here are for. I'm moving this discussion to Java in General (Beginner).