how to empty a variable in java code example

Example 1: java string is null or empty

public class Null {
 
	public static boolean isNullOrEmpty(String str) {
        if(str != null && !str.isEmpty())
            return false;
        return true;
    }
}

Example 2: how to check null and empty string in java

if(str != null && !str.isEmpty())
Be sure to use the parts of && in this order, because java will not proceed to evaluate the second part if the first part of && fails, thus ensuring you will not get a null pointer exception from str.isEmpty() if str is null.