Sun's Java Certifications ovevview

Sun has several forms of certification for Java,as shown below figure. 

Here is the list of possible Java certifications offered by Sun:

• Sun Certified Programmer for the Java 2 Platform, (two versions of the exam, 1.2 and 1.4)
• Sun Certified Programmer for the Java 2 Platform 1.4 Upgrade Exam
• Sun Certified Developer for the Java 2 Platform
• Sun Certified Web Component Developer for the Java 2 Platform, Enterprise Edition
• Sun Certified Enterprise Architect for J2EE Technology

The Certified Developer tests involve a programming project that you can complete on your own time, followed by an exam with questions related to your design decisions. The Web Component Developer exam focuses on Java technology for Web applications. The Architect certification involves more theoretical design considerations.

 Java SE Technology Certification Learning Path

SCJP Exam Objectives

Section 1: Declarations and Access Control

Write code that declares, constructs and initializes arrays of any base type using any of the permitted forms both for declaration and for initialization.
Declare classes, nested classes, methods, instance variables, static variables and automatic (method local) variables making appropriate use of all permitted modifiers (such as public, final, static, abstract, etc.). State the significance of each of these modifiers both singly and in combination and state the effect of package relationships on declared items qualified by these modifiers.
For a given class, determine if a default constructor will be created and if so state the prototype of that constructor.
Identify legal return types for any method given the declarations of all related methods in this or parent classes.

Section 2: Flow control, Assertions, and Exception Handling

Write code using if and switch statements and identify legal argument types for these statements.
Write code using all forms of loops including labeled and unlabeled, use of break and continue, and state the values taken by loop counter variables during and after loop execution.
Write code that makes proper use of exceptions and exception handling clauses (try, catch, finally) and declares methods and overriding methods that throw exceptions.
Recognize the effect of an exception arising at a specified point in a code fragment. Note: The exception may be a runtime exception, a checked exception, or an error (the code may include try, catch, or finally clauses in any legitimate combination).
Write code that makes proper use of assertions, and distinguish appropriate from inappropriate uses of assertions.
Identify correct statements about the assertion mechanism.

Section 3: Garbage Collection

State the behavior that is guaranteed by the garbage collection system.
Write code that explicitly makes objects eligible for garbage collection.
Recognize the point in a piece of source code at which an object becomes eligible for garbage collection.

Section 4: Language Fundamentals

Identify correctly constructed package declarations, import statements, class declarations (of all forms including inner classes) interface declarations, method declarations (including the main method that is used to start execution of a class), variable declarations, and identifiers.
Identify classes that correctly implement an interface where that interface is either java.lang.Runnable or a fully specified interface in the question.
State the correspondence between index values in the argument array passed to a main method and command line arguments.
Identify all Java programming language keywords. Note: There will not be any questions regarding esoteric distinctions between keywords and manifest constants.
State the effect of using a variable or array element of any kind when no explicit assignment has been made to it.
State the range of all primitive formats, data types and declare literal values for String and all primitive types using all permitted formats bases and representations.

Section 5: Operators and Assignments

Determine the result of applying any operator (including assignment operators and instance of) to operands of any type class scope or accessibility or any combination of these.
Determine the result of applying the boolean equals (Object) method to objects of any combination of the classes java.lang.String, java.lang.Boolean and java.lang.Object.
In an expression involving the operators &, |, &&, || and variables of known values state which operands are evaluated and the value of the expression.
Determine the effect upon objects and primitive values of passing variables into methods and performing assignments or other modifying operations in that method.

Section 6: Overloading, Overriding, Runtime Type and Object Orientation

State the benefits of encapsulation in object oriented design and write code that implements tightly encapsulated classes and the relationships "is a" and "has a".
Write code to invoke overridden or overloaded methods and parental or overloaded constructors; and describe the effect of invoking these methods.
Write code to construct instances of any concrete class including normal top level classes and nested classes.

Section 7: Threads

Write code to define, instantiate and start new threads using both java.lang.Thread and java.lang.Runnable.
Recognize conditions that might prevent a thread from executing.
Write code using synchronized wait, notify and notifyAll to protect against concurrent access problems and to communicate between threads.
Define the interaction among threads and object locks when executing synchronized wait, notify or notifyAll.

Section 8: Fundamental Classes in the java.lang Package

Write code using the following methods of the java.lang.Math class: abs, ceil, floor, max, min, random, round, sin, cos, tan, sqrt.
Describe the significance of the immutability of String objects.
Describe the significance of wrapper classes, including making appropriate selections in the wrapper classes to suit specified behavior requirements, stating the result of executing a fragment of code that includes an instance of one of the wrapper classes, and writing code using the following methods of the wrapper classes (e.g., Integer, Double, etc.):
o doubleValue
o floatValue
o intValue
o longValue
o parseXxx
o getXxx
o toString
o toHexString

Section 9: The Collections Framework

Make appropriate selection of collection classes/interfaces to suit specified behavior requirements.
Distinguish between correct and incorrect implementations of hashcode methods.

SCJP new 50 questions

Which two declarations prevent the overriding of a method? (Choose Two)

A. Final void methoda()  {}
B. Void final methoda() {}
C. Static void methoda() {}
D. Static final void methoda() {}
E. Final abstract void methoda() {}

Given:

1. public class Test {
2. public static void main (String args[]) {
3.   class Foo {
4.     public int i = 3;
5.    }
6.    Object o = (Object) new Foo();
7.    Foo foo = (Foo)o;
8.    System.out.printIn(foo. i);
9.    }
10. }

What is the result?

A. Compilation will fail.
B. Compilation will succeed and the program will print “3”
C. Compilation will succeed but the program will throw a ClassCastException at line 6.
D. Compilation will succeed but the program will throw a ClassCastException at line 7.

Given:

1. public class ExceptionTest {
2. class TestException extends Exception {}
3. public void runTest () throws TestException {}
4. public void test () /* Point X*/  {
5. runTest ();
6.   }
7. }

At point X on line 4, which code can be added to make the code compile?

A. Throws Exception.
B. Catch (Exception e).
C. Throws RuntimeException.
D. Catch (TestException e).
E. No code is necessary.

Which four types of objects can be thrown using the throw statement? (Choose Four)

A. Error
B. Event
C. Object
D. Exception
E. Throwable
F. RuntimeException

Which two can directly cause a thread to stop executing? (Choose Two)

A. Exiting from a synchronized block.
B. Calling the wait method on an object.
C. Calling the notify method on an object.
D. Calling the notifyAll method on an object.
E. Calling the setPriority method on a thread object.

Given:

2. public class Foo implements Runnable (
3. public void run (Thread t) {
4. system.out.printIn(“Running.”);
5. }
6. public static void main (String[] args)  {
7. new thread (new Foo()).start();
8. )
9. )

What is the result?

A. An exception is thrown.
B. The program exists without printing anything.
C. An error at line 1 causes compilation to fail.
D. An error at line 6 causes the compilation to fail.
E. “Running” is printed and the program exits.

Related Articles:

Exam Objectives of Java Collections Framework  for Sun Certified Programmer for Java 2 Platform 1.4 (CX-310-035)

Nested Classes and Static Nested Classes of Java 2™ Programmer Exam Cram™ 2 (Exam CX-310-035)