Eclipse equals generation: null check missing?

I let Eclipse generate the equals method for my class and it starts with:

@Override
public boolean equals(Object o开发者_如何学Pythonbj) {
    if (this == obj)
        return true;
    if (getClass() != obj.getClass())
        return false;
[...]

It seems to me, a check like if (obj == null) return false; is missing. Otherwise, if a null reference is passed to equals there will be a null pointer exception in obj.getClass(). Am I wrong or is Eclipse wrong?

Perhaps you are having an old eclipse version. My eclipse generates this:

if (this == obj)
    return true;
if (obj == null)
    return false;
if (getClass() != obj.getClass())
    return false;

You are right, if Eclipse does it that way. But it doesn't. On my machine, Eclipse Indigo / Ubuntu, given this Class:

public class Foo {
    private String bar;
}

Eclipse would generate the following equals() method:

@Override
public boolean equals(Object obj) {
    if (this == obj) return true;
    if (obj == null) return false;
    if (getClass() != obj.getClass()) return false;
    Foo other = (Foo) obj;
    if (bar == null) {
        if (other.bar != null) return false;
    } else if (!bar.equals(other.bar)) return false;
    return true;
}

For comparison, here's the equals() method I would write for the same class (using Guava):

@Override
public boolean equals(final Object obj) {
    return obj instanceof Foo ? Objects.equal(bar, ((Foo) obj).bar) : false;
    //          ^--- implicit null check here
}

I use this Eclipse code template to achieve this:

${:import(com.google.common.base.Objects)}
@Override
public boolean equals(final Object obj){
    return obj instanceof ${enclosing_type} ? Objects.equal(${field1:field}, ((${enclosing_type}) obj).${field1}) : false;
}

@Override
public int hashCode(){
    return Objects.hashCode(${field1});
}

@Override
public String toString(){
    return MoreObjects.toStringHelper(this).add("${field1}", ${field1}).toString();
}

Unfortunately, I have to keep one of these around for each cardinality of fields, so I have templates named eq1 (the above), eq2, eq3, eq4 etc. It's a small nuissance, but it's still a lot better than the monster methods generated by Eclipse. Guava docs

Yes, passing null as obj would give a NullPointerException with that code.

You indeed need a null check. My version of Eclipse generates equals methods with a null check.

if (obj) is null, the obj.getClass() will throw an NPE

It seems to me, a check like if (obj == false) return false; is missing.

Why do you want to compare object with a Boolean value? ;-)

I suppose you though about obj == null check, and that is exactly what Eclipse generates in my case:

@Override
      public boolean equals(Object obj)
      {
        if (this == obj)
          return true;
        if (obj == null)
          return false;
        if (getClass() != obj.getClass())
          return false;
        TestGetClass other = (TestGetClass) obj;
        if (id != other.id)
          return false;
        return true;
      }

I am using 3.7 version. Anyway, you are right... actually Eclipse... too ;-)