java isEmpty() undefined for string

Question

I'm working on a school project in eclipse, and when I try and use the isEmpty() method on a String, Eclipse shows up the following error:

"The method isEmpty() is undefined for the type String"

I've run the Java updates, but am still getting it. Is any reason why this method would be undefined?

Answer 1

According to http://java.sun.com/j2se/1.5.0/docs/api/java/lang/String.html there's no method isEmpty() for java.lang.String in Java 1.5, but in Java 1.6.

java -version

can tell you which version you really have.

Answer 2

String.isEmpty() was introduced in Java release 1.6. You might want to check what JDK version you're using for your project. (I don't know much about Eclipse myself, but it should be somewhere in the project settings.)

Answer 3

If you're not on Java 6, String.length() == 0 will return the same result as String.isEmpty().