This section of the site covers the requirements for the Java SE 6 Programmer Certified Professional Exam (IZO-851) which when passed gives the Oracle Certified Professional, Java SE 6 Programmer certification.
We will cover the seven topic areas of the exam as described at the Oracle Website.
In this section we look at all types of class declaration and extension and how to use interfaces and the package and import statements. We examine the declaration, initialization and usage of primitives, arrays, enums, and objects as static, instance, local variables and their respective scopes. After this we cover correct use of overriding and overloading of methods as well as identifying legal return values for methods. we investigate constructors to determine if a default constructor will be created, and if so, determine the behaviour of that constructor. We finish of this section by studying class instantiation and how to instantiate nested and non-nested classes.
In this section we look at the different syntax we can use to affect the flow of logic through our programs. We start by looking at code to implement if
switch statements whilst identifying legal argument types for them. We then investigate the different types of loops available in
java and the iterators and their usage within a loop. We will also look at how we can break from a loop, continue from within a loop and label a loop to continue execution from. We continue our study of flow
control by looking at assertions and when, and when not, they should be used. We finish our certification lessons on flow control by looking at exceptions, handling exceptions and how to declare methods and
overriding methods that throw exceptions. We also need to understand what happens to our code when an error or any type of exception occurs in a code fragment and what happens when particular exceptions occur.
We start this section by looking at code that uses the primitive wrapper classes and/or autoboxing and unboxing. We then look at the differences between the String, StringBuilder, and StringBuffer classes. After this
we investigate how we can use classes with the
java.io package to read from files, write to files and use the
PrintWriter sometimes in unison to create a software solution. We then use classes from the
java.text package to correctly format or parse dates, numbers, and
currency values for a specific locale including usage of the appropriate methods to use the default locale or a specific locale. We finish the section by looking at regular expressions and examine how to format and tokenize our data using Java6.
This section is all about concurrency and we start it by looking at thread definition, instantiation and execution using the
java.lang.Runnable classes. After this we investigate the different
states in which a thread can exist, and identify ways in which a thread can transition from one state to another. We finish the section by examining Java's locking mechanisms at the class and object level and
how we can synchronize methods and blocks of code to protect static or instance variables from concurrent access problems.
We start this section by looking at encapsulation, its advantages and how to achieve it within our code. We then look at the design principles of coupling and cohesion and describe the benefits of loose coupling and high cohesion. We then explain polymorphism and how we use it in the Java language before looking at object reference casting and determine when casting will be necessary whilst recognizing compiler vs. runtime errors, related to it. After this we examine the effect of modifiers on inheritance with respect to constructors, instance or static variables, and instance or static methods. We then look at code that declares and/or invokes overridden or overloaded methods and code that declares and/or invokes superclass or overloaded constructors. We finish the section by investigating code that implements "is-a" and/or "has-a" relationships.
We start this section by looking at the various types of collections and their corresponding interfaces and which type of collection is suitable for specific types of data. We then look at usage of
the Comparable interface. After this we look at the
equals() method of the
Object class which only ever returns
true when the reference variables refer to the same object which
isn't helpful when we want our collections sorted and stored dependent upon fields in the collection. So in this lesson we look at correct and incorrect overrides of corresponding
hashCode() methods and explain the difference between
== and the
equals() method. Generics were introduced with Java6 and in this lesson we look at the reasons for doing
this. We then look at usage of type parameters in class/interface declarations, instance variables, method arguments, and return types. We finish the lesson by looking at generic methods as well as methods that
make use of wildcard types. We finish the section by looking at array and list manipulation using the
java.util package, usage of the
interfaces for sorting collections and the effect of natural ordering of primitive wrapper classes and
java.lang.String on sorting.
In our first lesson within this section we look at access modifiers and also investigate the package and import statements. We then look at the
javac command we use to compile our Java programs and
java command to run our programs. We finish the lesson with a look at JAR files and how to use them. After this we look at method parameters that are passed into methods as reference variables
and primitive variables and the effects that modification within the methods has on the variable type in question. We then examine the point at which an object becomes eligible for garbage collection, and determine
what is and is not guaranteed by the garbage collection system and how the behaviors of
System.gc and finalization impact this. In our final lesson within this section we look at the various operators that are
available in Java and how to use them.