True or false

1. Java source code files can contain more than one class definition 2. package is a reserved word modifier in Java that signals that a class's members 3. Abstraction is one of the themes of computer science 4. According to the object-oriented metaphor, everything is an object and can be accessed by any other class stored in the same directory computation only ever occurs when objects are copied. 5. T 6. An ADT is an Abstract Data Type. 7. All of the ways that the word "interface" is used in object-oriented he syntax and semantics of Java require that the class hierarchy, the interface hierarchy, and the package hierarchy all have an identical structure programming in Java have in common the idea of providing a mechanism for communicating information between two or more entities. 8. An algorithm that has run time performance of O(n 1g n) is expected to take less time than an algorithm that is quadratic, most of the time. 9. Classes that are declared to be abstract cannot be instantiated. Most relationships between objects and classes can be characterized by either "is a" or "has a". 10