String comparison and String interning in Java

When should one compare Strings as objects and when should one use their equals method? To make sure, I always use equals, but that doesn't seem very efficient. In what situations can I be certain that string1 == string2 is a safe to use?

You should almost always use equals. You can be certain that string1 == string2 will work if:

• You've already made sure you've got distinct values in some other way (e.g. you're using string values fetched from a set, but comparing them for some other reason)
• You know you're dealing with compile-time string constants
• You've manually interned the strings yourself

It really doesn't happen very often, in my experience.