distingush between abstract and adopter class in java when A class is An abstract means it declared with keyword as public followed by asbtract. this makes abstract class can be only contain empty methods which are un implemented.An abstract class cannot be instantiated. Adapter is a special class that acts as an itermediary between class and interface, therefore every interface comes with an adapter with list of methods in it. interface contains purely abstract class, this means you can't define an interface mothods,therefore an interface consist of methods which are off typed as public and abstract only also as to a variables which are off typed to as public static final types. 2.a checked exception during compiler process the compiler checks whether exception has been handled or not such exceptions are (IOExceptions error) since the program cant void such erorrs. unchecked exception are those which compiler doesnt flag as potentially error-prone during compiler runtime exceptions. distingush between the following three types of collections in java List interface the list interface specifies the mothods required to process an ordered list of objects and such list may contain repeatitions. set interface the set interafce defines the mothods required to process a collection of objects in which there is no repeatition and ordeing is unimportant. Map interface the map interface defines the methods required to process a collection of objects consisting of pairs of objects( keys and values) Briefly describe how the generic mechanism of java works the generics mechanism allows us to send one or more types to a class or inteface as a perameter Describe each of the following ways of encoding data text encoding the text encoding means that the data are stored as a charecter whereas on the other hand binary encoding, means that the data is stored in the same format as the internal representation used by the program to store data in memory. Describe what is mean by an enumerated type and illustrate how the enumerated PlaneStatus type was represented in UML. enumerated is type that consist of a few possible values each with meaningful name is refered to as an enumerated type. <<enumeration>> planeStatus DUE WAITING LANDING DEPARTURE TOOL TIP The Swing components support the ability to display brief popup messages when the user rests the mouse cursor over them. While the class used to display popup messages is JToolTip, you never create instances directly. Instead, you call the setToolTipText(String text) JComponent, which triggers the text to be displayed at the appropriate time. immutable objects is object which has no methods to alter their state are know as immutable object. applet is a java program that is downloaded and run from web browser threads is each separate task performed by a single program.
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