Question

Possible Duplicate:
Java String.equals versus ==

I thought this would be a neat way of structuring a picker method but the output is not going to the first two if statements and only outputs the last

    public int myPickerMethod(){

        System.out.println("please select from the options ");
        System.out.println("please select 1 for option 1 ");
        System.out.println("please select 2 please select 2 for option 2");
        String input = keyboard.readLine();
        System.out.println("input = " + input);     

        if(input=="1"){

                return 1;
        }
        else if(input=="2"){
            return 2;
        }
        else{
            return 42;
        }
   }

Here is my result from the terminal:

   please select from the options 
   please select 1 for option 1 
   please select 2 please select 2 for option 2
   1
   input = 1
   response = 42

Same goes if I put 2 in. the “response” print statement is the output from the method from a print statement in the main class.

I have not tried this way before but I figured it should work. I don’t really get why it isn’t. Anyone able to clear this up? Thanks

Answer 1

For testing Object (non-primitive type) equality, use Object.equals().

if(input.equals("1")) {

    return 1;
}

The == operator checks whether the references to the objects are equal. A test for reference equality is done within the String.equals() method, among other checks. Below is the Java source for the String.equals() method:

public boolean equals(Object anObject) {
     if (this == anObject) {      // Reference equality
         return true;
     }
     if (anObject instanceof String) {
         String anotherString = (String)anObject;
         int n = count;
         if (n == anotherString.count) {  // Are the strings the same size?
             char v1[] = value;
             char v2[] = anotherString.value;
             int i = offset;
             int j = anotherString.offset;
             while (n-- != 0) {
                 if (v1[i++] != v2[j++])        // Compare each character
                     return false;
             }
             return true;
         }
     }
     return false;
}