public class Foobar {
public static void main(String[] args) {
// example:
Boolean ignore = null;
if (ignore == false) {
System.out.println("Do not ignore!");
}
}
}The pitfall here is that null is compared to false. Since we’re comparing a primitive boolean against a Boolean, Java attempts to unbox the the Boolean Object into a primitive equivalent, ready for comparison. However, since that value is null, a NullPointerException is thrown.
Java is incapable of comparing primitive types against null values, which causes a NullPointerException at runtime. Consider the primitive case of the condition false == null; this would generate a compile time error incomparable types: int and <null>.