An API is a contract between a caller and a callee. The most common forms of API abuse are caused by the caller failing to honor its end of this contract. For example, if a program fails to call chdir() after calling chroot(), it violates the contract that specifies how to change the active root directory in a secure fashion. Another good example of library abuse is expecting the callee to return trustworthy DNS information to the caller. In this case, the caller abuses the callee API by making certain assumptions about its behavior (that the return value can be used for authentication purposes). One can also violate the caller-callee contract from the other side. For example, if a coder subclasses SecureRandom and returns a non-random value, the contract is violated.
Code Correctness: Class Does Not Implement Equivalence Method
Equals() is called on an object that does not implement Equals().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 System.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 Gid
{
get { return gid; }
set { gid = value; }
}
}
...
public class CompareGroup
{
public bool compareGroups(AccountGroup group1, AccountGroup group2)
{
return group1.Equals(group2); //Equals() is not implemented in AccountGroup
}
}
equals() method is called on an object that does not implement equals().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
}
}