Designing Classes

Avoid finalizers as they slow down performance and run non-deterministically or may never run at all. Use try-with-resources or try-with-finally to ensure code cleanup.

Overriding equals() method should honour the following properties:

• Reflexivity: x.equals(x) == true

• Symmetric: x.equals(y) == y.equals(x)

• Transitivity: x.equals(y) == y.equals(z) == z.equals(x)

• Consistent: x.equals(y) == x.equals(y) == x.equals(y) == ...

• Non-nullity: x.equals(null) should equal false

Always override hashCode() when you override equals()

Overriding hashCode() should honor the following properties:

• Invoking hashCode() on the same object should always return the same integer.

• If there are two objects x and y and x.equal(y) then ...