ABSTRACT

The equals() method is called on an object that does not implement equals().

EXPLANATION

When comparing objects, developers developers usually want to compare properties of objects. However, calling equals() on a class (or any super class/interface) that does not explicitly implement equals() results in a call to the equals() method inherited from java.lang.Object. Instead of comparing object member fields or other properties, Object.equals() compares two object instances to see if they are the same. Although there are legitimate uses of Object.equals(), it is often an indication of buggy code.

Example 1:


public class AccountGroup
{
private int gid;

public int getGid()
{
return gid;
}

public void setGid(int newGid)
{
gid = newGid;
}
}
...
public class CompareGroup
{
public boolean compareGroups(AccountGroup group1, AccountGroup group2)
{
return group1.equals(group2); //equals() is not implemented in AccountGroup
}
}


REFERENCES

[1] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 398