Java Strings

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In this blog we look at some quirky dealings with Java Strings. We'll be using concepts of Java variables, data-types and operators and especially Strings.

The following code constructs two strings s1 and s2. When they are compared, their contents are identical.

String s1 = "12345";
String s2 = "123";
s2 += "45";
if(s1 == s2) {
    System.out.println(s1 + " equals " + s2);
} else {
    System.out.println(s1 + " does NOT equal " + s2);
}

Strangely, this code reports that the strings are not equal:
12345 does NOT equal 12345 

Why is that? How do we fix this? Notice the change in bold below.

String s1 = "12345";
String s2 = "123";
s2 += "45";
if(s1.equals(s2)) {
    System.out.println(s1 + " equals " + s2);
} else {
    System.out.println(s1 + " does NOT equal " + s2);
}

Now it looks ok:
12345 equals 12345 

What's going on here? Do you think there are other Java types have this 'issue' as well?

 Once you've figured it out, let's explore characters in Java

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