Advanced Java Lecture Notes 12-10 PDF

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Lecture Notes from Advanced Java, Chapters 1-4...

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Advanced Java: Lecture Notes 12/10/18

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Generics are important to Java because they enable the creation of code that is o Type-safe o Reusable o Reliable

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Can a primitive type be used as a type argument? o No, type argument must be object types

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Show how to declare a class called FllghtSched that takes two generic parameters. o class FlightSched {

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Can the wildcard argument be bounded? o Yes, a wild card can have either an upper or lower bound

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Do type parameters exist at run time? o No, all type parameters are erased during compliation, and appropriate casts are substituted

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All methods in an abstract class must be decalred as abstract methods o False

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Invoking a subclass-only method through a subclass variable is not allowed o False

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If a superclass declares an abstract method, a subclass must implement that method. o False

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An object of a class that implements an interface may be thought of as an object of that interface type o True

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An annotation is syntactically based on a/an: o Interface

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A marker annotation is: o One that does not take any arguments.

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An annotation can be applied only to methods. o False

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@Override public String toStringQ { Return String.format("o/os: o/os o/os\no/os: o/os\no/os: %.2f\no/os: %.2f', "commission employee", firstName, lastName, "social security number", socialSecurityNumber, "gross sales", grosssales, "commission rate", commissionRate); } //end method toString o @Override annotation is used to indicate that method toString should override a superclass method.

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What method is called when an applet first begins running? o init0

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What method is called when an applet is removed from the system? o destroy()

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Which method is invoked for an applet each time a browser's user leaves an HTML page on which the applet resides? o Stop

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Every applet should extend class o Applet OR JApplet

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Which of the followings can be used to execute a Java applet? o appletviewer or a browser

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What method is invoked to draw on an applet o Paint

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The HTML tags that we use to specify that an applet should be loaded into an applet container and executed. o ,

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Multithreading is supported by the o Thread class and the Runnable interface

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When creating a runnable object, why might you want to extend Thread rather than implement Runnable? o When you want to override one or more of Thread's methods other than run().

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Show how to use joinO to wait for a thread object called MyThrd to end o MyThrd.joinQ;

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Show how to set a thread called MyThrd to three levels above normal priority o MyThrd.setPriority(Thread.NORM_PRIORITY + 3);

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Adding synchronized to a method allows only one thread at a time to use the method for any given object of its class. o True

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The waitQ and notifyQ methods are used to perform o interthread communication

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What method defined by Thread obtains the name of a thread? o getName()

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What does isAliveQ return? o true if the invoking thread is still running OR false if the invoking thread has been terminated

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Why can't you use suspend(), resume(), and stop() for new programs? o The three methods have been deprecated because they can cause serious run-time problems.

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Exception UnknownHostException occurs when o a hostname indicated by a client cannot be resolved to an address.

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Exception IOException occurs when o an input/output error occurs when closing a socket.

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Many of Java's networking classes are contained in package o Java.net

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An object of class ___ contains an IP address o lnetAddress

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Class ____ binds the application to a port for datagram transmission o DatagramSocket

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With stream sockets a process establishes a connection to another process o True

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Statement objects return SQL query results as o ResultSet object

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SQL keyword ____ is followed by the selection criteria that specify the rows to select in a query o WHERE

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Merging rows from multiple database tables is called o joining tile tables

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Drivermanager method getconnection is used to o obtain a connection to a database

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A disconnected Rowset, caches the data of a ResultSet in memory o CachedRowSet...