How to prevent null check before equals

Question

I find stuff like this rather annoying and ugly in equals methods:

if (field == null)
{
    if (other.field != null)
        return false;
}
else if ( ! field.equals(other.field))
    return false;

In C# I could've done this:

if( ! Object.Equals(field, other.field))
    return false;

Is there something similar in Java, or what is the preferred way to do this kind if thing?

Answer 1

Java 7 offers java.util.Objects.equals.

Answer 2

Use commons-lang:

org.apache.commons.lang.ObjectUtils.equals(Object object1, Object object2) 

Source code:

public static boolean equals(Object object1, Object object2) {     if (object1 == object2) {         return true;     }     if ((object1 == null) || (object2 == null)) {         return false;     }     return object1.equals(object2); } 

From Apache

http://commons.apache.org/lang/

That's about equivalent to what you do in C#

Answer 3

Guava equal which does this :

public static boolean equal(@Nullable Object a, @Nullable Object b) {
    return a == b || (a != null && a.equals(b));
  }

or null object pattern

Guava also has the somewhat related comparison chain and a load of other goodies.

Answer 4

I would write it this way:

return field != null && other.field != null && field.equals(other.field);

which is not as elegant as the C# code line, but much shorter then the if tree you posted.