There are two POJO classes employee and certificates which has one to many mapping. The following is a method in certificates class. What is the purpose of this method?

public boolean equals(Object obj) {
if (obj == null) return false;
if (!this.getClass().equals(obj.getClass())) return false;
Certificate obj2 = (Certificate)obj;
if((this.id == obj2.getId()) && (this.name.equals(obj2.getName())))
{
return true;
}
return false;
}

There is this other code called hashCode. what is its purpose?
public int hashCode() {
int tmp = 0;
tmp = ( id + name ).hashCode();
return tmp;
}
}

Since these two methods are overrides of methods defined in java.lang.Object
you find a good description here:
http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html

I guess the Certificate class has some super class. You may need to go through the full code flow.