The elements of a GridBagLayout are organized according to a grid. However, theelements are of differentsizes and may occupy more than one row or column of the grid. In addition, the rows andcolumns mayhave different sizes.

Java uses layout managers to lay out components in a consistent manner across allwindowing platforms.Since Java's layout managers aren't tied to absolute sizing and positioning, they are ableto accomodateplatform-specific differences among windowing systems.

A static variable is associated with the class as a whole rather than with specific instancesof a class. Nonstaticvariables take on unique values with each object instance.

The operating system's task scheduler allocates execution time to multiple tasks. Byquickly switchingbetween executing tasks, it creates the impression that tasks execute sequentially.

When a task's interrupt() method is executed, the task enters the ready state. The nexttime the task entersthe running state, an InterruptedException is thrown.

There are two types of casting, casting between primitive numeric types and castingbetween objectreferences. Casting between numeric types is used to convert larger values, such asdouble values, tosmaller values, such as byte values. Casting between object references is used to refer toan object by acompatible class, interface, or array type reference.

The JDK 1.02 event model uses an event inheritance or bubbling approach. In this model,components arerequired to handle their own events. If they do not handle a particular event, the event isinherited by (orbubbled up to) the component's container. The container then either handles the event orit is bubbled up toits container and so on, until the highest-level container has been tried.In the event-delegation...

The == operator compares two objects to determine if they are the same object inmemory. It is possible fortwo String objects to have the same value, but located indifferent areas of memory.

The enableEvents() method is used to enable an event for a particular object. Normally,an event is enabledwhen a listener is added to an object for a particular event. The enableEvents() method isused by objectsthat handle events by overriding their event-dispatch methods.

The File class encapsulates the files and directories of the local file system. TheRandomAccessFile classprovides the methods needed to directly access data contained in any part of a file.

If you are running Java on English Windows platforms, it is probably Cp1252. If you arerunning Java onEnglish Solaris platforms, it is most likely 8859_1..

Overridden methods must have the same name, argument list, and return type. Theoverriding method maynot limit the access of the method it overrides. The overriding method may not throwany exceptions thatmay not be thrown by the overridden method.

The exception propagates up to the next higher level try-catch statement (if any) orresults in the program'stermination.

Numeric promotion is the conversion of a smaller numeric type to a larger numeric type,so that integer andfloating-point operations may take place. In numerical promotion, byte, char, and shortvalues areconverted to int values. The int values are also converted to long values, if necessary.The long and floatvalues are converted to double values, as required.

The prefix form performs the increment operation and returns the value of the incrementoperation. Thepostfix form returns the current value all of the expression and then performs theincrement operation onthat value.

A Java package is a naming context for classes and interfaces. A package is used tocreate a separate namespace for groups of classes and interfaces. Packages are also used to organize relatedclasses and interfacesinto a single API unit and to control accessibility to these classes and interfaces.

When an exception is thrown within the body of a try statement, the catch clauses of thetry statement areexamined in the order in which they appear. The first catch clause that is capable ofhandling the exceptionis executed. The remaining catch clauses are ignored.

Synchronized methods are methods that are used to control access to an object. A threadonly executes asynchronized method after it has acquired the lock for the method's object or class.Synchronizedstatements are similar to synchronized methods. A synchronized statement can only beexecuted after athread has acquired the lock for the object or class referenced in the synchronizedstatement.

A thread class may be declared as a subclass of Thread, or it may implement theRunnable interface.

Without layout managers, Java programmers are faced with determining how their GUIwill be displayedacross multiple windowing systems and finding a common sizing and positioning thatwill work within theconstraints imposed by each windowing system.