CODEWITHSUNDEEP
javastringif-statement
sarsarahman
sarsarahman

Reputation: 1088

Why is my if condition comparing strings failing?

This program execution is not getting inside the if condition.
please check the comment i have specified.

public static void filterObject(ArrayList<treewalker.VariableNode> variableNodeslist,
            ArrayList<treewalker.ObjectNode> objectNodeslist,
            ArrayList<treewalker.ClassNode> classNodeslist) {
        int i, j;
        for (i = 0; i < variableNodeslist.size(); i++) {
            for (j = 0; j < classNodeslist.size(); j++) {
                String argu1 = variableNodeslist.get(i).typeClass.toString();
                String argu2 = classNodeslist.get(j).name.toString();
                System.out.println(argu1);
                System.out.println(argu2);
                if (argu1 == argu2)//this if loop is not getting executed 
                {
                    System.out.println("inside for");
                }
                System.out.println("hi");
            }
        }
    }

Upvotes: 3

Views: 429

Answers (5)

Philip Fourie
Philip Fourie

Reputation: 116837

Short answer:
argu1.equals(argu2) instead of argu1 == argu2


Longer answer:
The == operator in Java does a reference compare.

You want to do string comparison, use:

if (argu1.equals(argu2))


In some case the == operator might seem to do a equality check for example:

String var1 = "abc";
String var2 = "abc";

String result = ("abc" == "abc");

In this case the result is true which at first look seems to be an equality comparison but is fact a compiler optimisation where both var1 and var2 shares the same reference.

Upvotes: 3

Shahzeb
Shahzeb

Reputation: 4785

Use if(argu1.equals(argu2)) not if(argu1==argu2)

You should never use == to compare strings.

Upvotes: 1

TotoroTotoro
TotoroTotoro

Reputation: 17612

Use String.equals() to compare your strings, not ==.

Upvotes: 1

Ashwini Raman
Ashwini Raman

Reputation: 986

you should be doing if(argu1.equals(argu2)) for string comparision. == will compare the hashcode. For Strings, even thought the 2 strings contain the same text, their hashcodes may differ. Hence you need to use equals() to compare the string text

Upvotes: 1

Shashank Kadne
Shashank Kadne

Reputation: 8101

Use equals

argu1.equals(argu2)

Upvotes: 1

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