False false. cate whether the statement is true or 1. An abstract method must not have any executable code. 2. A class can extend an interface. 3. A class that implements an interface can include methods that are not required by the interface. 4. An interface definition can include constant declarations. s. In a non-empty stack, the item that has been in the stack the longest is at the bottom of the stack. 6. The first element to be stored in a stack is also the first element removed from the stack. 7. For a non-empty stack, top retums the value of the most recent item pushed onto the stack. 8. Object-oriented classes, when designed properly, are easy to reuse. 9. Aprivate variable cannot be accessed from anywhere 10. package can be split among several files 11. A queue is a first in, first out structure. An array whose elements are sorted is a sorted list. 13. An alias is when we have two variables referring to the same object. 14, Arrays of objects are supported by Java. 15. Java programmers can define their own exceptions