java - toUpperCase not functioning as I'd expect

I have two Strings; one is "hello" in lower case and one is "HELLO" in upper.

When I apply toUpperCase to the variables and then use a boolean to compare them, they are coming out as not equal and I can't figure out why.

public static void main(String[] args) {

    String a = "hello";
    String b = "HELLO";

    a = a.toUpperCase();
    b = b.toUpperCase();


    boolean c = (a==b);

    System.out.println(b + " " + a + " " + c);
}

The output is HELLO HELLO false but it should be HELLO HELLO true. Shouldn't it?
What am I missing?

Answer

toUpperCase is working correctly. You have to use equals to check for equality of both Strings.

boolean c = a.equals(b);