i would like to know whether java i/o is been included in the programmers exam. if it is so, how much depth we've to go into it. is it required to go through the garbage collection , concepts like strong references,weak references, phantom references etc, for programmers exam. what is actually the necessity of having an interface in java. please give me an example where it is unavoidable.
Java I/O has always been a part of the certification exam. You will need to know the hierarchy of streams, the different interfaces and classes involved in the i/o package. You will need to know the basic differences betweeen byte oriented and character oriented i/o, and how streams support unicode format. You will also need to know "chaining" of streams in order to achieve required functionality. You may not get many questions on Garbage collection, though it is a part of the SCJP objectives. You should know when an object becomes eligible for garbage collection, and how finalize method is used. Advance GC concepts are not requried. Since Java doesnot support multiple inheritance, interfaces provide a better alternative to implement branched hierarchies. This is perhaps the most commonly cited application of interfaces, without which there is no other way to implemement multiple inheritance. Ofcourse there are other benefits too! Ajith
Open Group Certified Distinguished IT Architect. Open Group Certified Master IT Architect. Sun Certified Architect (SCEA).
Interfaces give you fantastic flexibility in designing classes since there is no limit on the combinations. For example, I occasionally make classes that implement Runnable and Observer. And of course, there are uses such as Serializable where the interface serves as a kind of marker. Look around in the standard library at how some of the interfaces and abstract classes are used.