Java Object-Oriented Programming Competency

Topics covered

• apply the methods of the Exception base class to obtain exception information
• appropriately override the .toString method provided by the Object base class
• avoid pitfalls related to re-initialization and modification of objects (reference types) while invoking functions in Java
• combine multiple independent catch blocks using the | operator
• combine multiple related catch blocks using the | operator
• correctly chain constructors to achieve code reuse
• correctly declare or handle exceptions in a chain of functions, each of which throws different types of exceptions
• correctly initialize objects of inner classes
• correctly initialize objects of static nested classes
• correctly invoke a method that throws an exception of a checked exception type
• correctly place the finally block relative to the catch blocks
• define and use static member variables
• differentiate between the semantics of throwing runtime exceptions vs. throwing checked exceptions
• implement exception handling in a chain of methods that sequentially call each other
• implement the Serializable interface in user-defined classes so that they can be written to and read from using ObjectOutputStream and ObjectInputStream objects
• instantiate and throw custom exception objects of both checked and unchecked exception types
• invoke static and non-static methods of a class
• recognize how static methods can be accessed by instances of a class
• recognize how variables of primitive types are governed by pass-by-value semantics in Java
• recognize how variables of reference types are governed by pass-by-reference semantics in Java
• recognize the exact semantics and limitations of the finally block
• recognize the precise semantics of the try-with-resources construct in Java
• use initialization blocks to appropriately initialize static and non-static member variables
• use multiple independent catch blocks with a single try block
• use the BufferedReader and BufferedWriter classes to efficiently interact with character streams
• use the DataInputStream class to read primitive types and strings from byte streams
• use the ObjectOutputStream class to write objects of any type to byte streams