Difference between isEmpty() and zero length

Question

What is the difference between these two methods?

public boolean nameControl(String str) 
{
    if (str.trim().isEmpty()) return false;
    if (str.trim().length() == 0) return false;
    return true;
}

I need find out that str should have at least one character.

Answer 1

There is no real difference between them.

Javadocs for isEmpty()

Returns true if, and only if, length() is 0.

Answer 2

From the Javadoc:

isEmpty

public boolean isEmpty()

Returns true if, and only if, length() is 0.