CODEWITHSUNDEEP
javanull
User1
User1

Reputation: 41193

Checking if two objects are equal even if they could be null

Sometimes, I see this:

if (a.equals(b)) do(something);

However, if a is null, a NullPointerException is thrown. Assuming when a==null and b==null or if just a==b that I would want to do(something). What's the simplest way to do this check without getting an exception?

Upvotes: 10

Views: 7437

Answers (2)

McDowell
McDowell

Reputation: 108899

if( a==b || (a!=null && a.equals(b)) )

(The a==b handles the case when both are null.)

Also be aware of the Java 7 and above Object.equals method:

if(java.util.Object.equals(a, b))

Upvotes: 22

Peter Lawrey
Peter Lawrey

Reputation: 533530

Another way of writing it.

if (a == null ? b == null : a.equals(b))

Upvotes: 24

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