java string is not null 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: check if a string is empty java

if (myString == null || myString.equals(""))
			throw new IllegalArgumentException("empty string");