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What is more advisable to create a thread, by implementing a Runnable interface or by extending Thread class?
What is more advisable to create a thread, by implementing a Runnable interface or by extending Thread class? Strategically speaking, threads created by implementing Runnable interface are more advisable. If you create a thread by extending a thread class, you cannot extend any other class. If you c... 2012-05-17, 3070👍, 0💬

What is the relationship between synchronized and volatile keyword?
What is the relationship between synchronized and volatile keyword? The JVM is guaranteed to treat reads and writes of data of 32 bits or less as atomic.(Some JVM might treat reads and writes of data of 64 bits or less as atomic in future) For long or double variable, programmers should take care in... 2012-08-28, 3068👍, 0💬

How are Observer and Observable used?
How are Observer and Observable used? Objects that subclass the Observable class maintain a list of observers. When an Observable object is updated, it invokes the update() method of each of its observers to notify the observers that it has changed state. The Observer interface is implemented by obj... 2012-05-31, 3066👍, 0💬

If a method is declared as protected, where may the method be accessed?
If a method is declared as protected, where may the method be accessed? A protected method may only be accessed by classes or interfaces of the same package or by subclasses of the class in which it is declared. 2012-06-21, 3058👍, 0💬

Jack developed a program by using a Map container to hold key/value pairs. He wanted to make a change to the map. He decided to
Jack developed a program by using a Map container to hold key/value pairs. He wanted to make a change to the map. He decided to make a clone of the map in order to save the original data on side. What do you think of it? ? If Jack made a clone of the map, any changes to the clone or the original map... 2012-05-16, 3058👍, 0💬

How many methods in the Externalizable interface?
How many methods in the Externalizable interface? There are two methods in the Externalizable interface. You have to implement these two methods in order to make your class externalizable. These two methods are readExternal() and writeExternal(). 2012-05-29, 3056👍, 0💬

Can a .java file contain more than one java classes?
Can a .java file contain more than one java classes? Yes, a .java file contain more than one java classes, provided at the most one of them is a public class. 2013-06-24, 3047👍, 0💬

How does multi-threading take place on a computer with a single CPU?
How does multi-threading take place on a computer with a single CPU? The operating system's task scheduler allocates execution time to multiple tasks. By quickly switching between executing tasks, it creates the impression that tasks execute sequentially. 2012-06-08, 3046👍, 0💬

What class is the top of the AWT event hierarchy?
What class is the top of the AWT event hierarchy? The java.awt.AWTEvent class is the highest-level class in the AWT event-class hierarchy. 2012-10-12, 3043👍, 0💬

Can you have virtual functions in Java?
Can you have virtual functions in Java? Yes, all functions in Java are virtual by default. This is actually a pseudo trick question because the word "virtual" is not part of the naming convention in Java (as it is in C++, C-sharp and VB.NET), so this would be a foreign concept for someone who has on... 2012-05-16, 3034👍, 0💬

What are the high-level thread states?
What are the high-level thread states? The high-level thread states are ready, running, waiting, and dead. 2012-06-15, 3030👍, 0💬

What is the difference between Serializalble and Externalizable interface?
What is the difference between Serializalble and Externalizable interface? When you use Serializable interface, your class is serialized automatically by default. But you can override writeObject() and readObject() two methods to control more complex object serailization process. When you use Extern... 2012-05-29, 3027👍, 0💬

An application needs to load a library before it starts to run, how to code??
An application needs to load a library before it starts to run, how to code?? One option is to use a static block to load a library before anything is called. For example, class Test { static { System.loadLibrary("path-to-li brary-file");} .... } When you call new Test(), the static block will be ca... 2012-05-18, 3018👍, 0💬

What is similarities/difference between an Abstract class and Interface?
What is similarities/difference between an Abstract class and Interface? Differences are as follows: Interfaces provide a form of multiple inheritance. A class can extend only one other class. Interfaces are limited to public methods and constants with no implementation. Abstract classes can have a ... 2012-05-23, 3017👍, 0💬

What are wrapped classes?
What are wrapped classes? Wrapped classes are classes that allow primitive types to be accessed as objects. 2012-06-25, 3015👍, 0💬

What is the immediate superclass of the Dialog class?
What is the immediate superclass of the Dialog class? Window. 2012-10-05, 3012👍, 0💬

What is the numeric promotion?
What is the numeric promotion? Numeric promotion is used with both unary and binary bitwise operators. This means that byte, char, and short values are converted to int values before a bitwise operator is applied. If a binary bitwise operator has one long operand, the other operand is converted to a... 2012-07-02, 3012👍, 0💬

How many methods in the Serializable interface?
How many methods in the Serializable interface? There is no method in the Serializable interface. The Serializable interface acts as a marker, telling the object serialization tools that your class is serializable. 2012-05-28, 3003👍, 0💬

What is the difference between the File and RandomAccessFile classes?
What is the difference between the File and RandomAccessFile classes? The File class encapsulates the files and directories of the local file system. The RandomAccessFile class provides the methods needed to directly access data contained in any part of a file. 2013-01-08, 2998👍, 0💬

What are synchronized methods and synchronized statements?
What are synchronized methods and synchronized statements? Synchronized methods are methods that are used to control access to a method or an object. A thread only executes a synchronized method after it has acquired the lock for the method's object or class. Synchronized statements are similar to s... 2012-06-04, 2998👍, 0💬

What is a transient variable?
What is a transient variable? A transient variable is a variable that may not be serialized. 2012-09-13, 2995👍, 0💬

What is the difference between throw and throws keywords?
What is the difference between throw and throws keywords? The throw keyword denotes a statement that causes an exception to be initiated. It takes the Exception object to be thrown as argument. The exception will be caught by an immediately encompassing try-catch construction or propagated further u... 2012-07-19, 2994👍, 0💬

How the object oriented approach helps us keep complexity of software development under control?
How the object oriented approach helps us keep complexity of software development under control? We can discuss such issue from the following aspects: Objects allow procedures to be encapsulated with their data to reduce potential interference. Inheritance allows well-tested procedures to be reused ... 2012-08-14, 2991👍, 0💬

What is a transient variable?
What is a transient variable? A transient variable is a variable that may not be serialized. If you don't want some field to be serialized, you can mark that field transient or static. 2012-05-30, 2987👍, 0💬

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.NET C C++ CSS DBA General HTML Java JavaScript JSP JUnit MySQL Networking Oracle Perl Perl PHP PL/SQL RSS Software QA SQL Server Struts Unix Windows XHTML XML