Few comments:

• The name StackMethods is not the best name for this, you should rather pick a name that describes your entity, eg: Stack

• Your class only works for integers, where Stack is an ADT that should accept various types, so consider using generics instead

   class Stack<T>{ private T[] stackArray; } 

• the fields : size, and stack have package access, and this means classes within the same package can modify them

• You should throw an unchecked exception in push method if the stack is full rather than printing something to the console

Few comments:

• The name StackMethods is not the best name for this, you should rather pick a name that describes your entity, eg: Stack

• Your class only works for integers, where Stack is an ADT that should accept various types, so consider using generics instead

   class Stack<T>{ private T[] stackArray; } 

• the fields : size, and stack have package access, and this means classes within the same package can modify them, declare them as private instead.

• You should throw an unchecked exception in push method if the stack is full rather than printing something to the console