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Wha is the output from System.out.println("Hello"+null);?
Wha is the output from System.out.println("Hello"+nul l);?Hellonull
2023-08-24, 7829👍, 1💬

💬 2023-08-24 DIMITRI: THIS IS GOOD

Java String Interview Question
If we have the following in a Java code: String s="abc"; String s2="abc"; Then what will be output of: System.out.println("s.equals(s 2)= "+s.equals(s2)); System.out.println("s==s2 = "+(s==s2)); The correct answer is: s.equals(s2) = true s==s2 = true The following answer is wrong. Because both liter...
2016-06-26, 14503👍, 2💬

💬 2011-01-25 FYIcenter.com: Hi Kevin, Thanks. Answer updated.

💬 2011-01-17 Kevin McLain: This answer is wrong! String literals are interned by the VM this both will print true

Creating a New Thread
How to create a thread in a program? You have two ways to do so. First, making your class "extends" Thread class. Second, making your class "implements" Runnable interface. Put jobs in a run() method and call start() method to start the thread.
2016-06-25, 434756👍, 8💬

💬 2016-06-25 Ron: You can also create an anonymous class and run it: Thread t = new Thread() { public void run() { // do whatever you want } }; t....

💬 2013-10-02 drinkin: This unmistakably created an audience for books fact that consciously offered the grand design models

💬 2013-07-23 XRumerTest: Hello. And Bye.

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Binary value in Switch case
Is it possible to pass a binary value to 'case' of 'switch' statement?The control value which we are using to test is also binary. switch(binary value) { case 0000: System.out.println(" "); break; case 0001: System.out.println(" "); break; }
2014-02-20, 2186👍, 0💬

Calculating Total Weight of Subtree
Subject: Calculating Total Weight of Subtree --- Category: ,1, --- Question Can you write a computer code for the following problem: Given a text file with 3 comma-delimited columns of all integers: 'id', 'parent' and 'weight'. Each line represents a node identified by 'id'. 'parent' refers to 'id' ...
2014-01-02, 3027👍, 0💬

Calculating Most Frequent Number
Can you write a computer code for the following problem: Given an online stream of infinite numbers, print out the most frequent number. Here is a solution in Java: import java.io.*; import java.util.*; public class MostFrequent { public static void main(String[] a) { int mapMax = 99; // Most freque...
2013-12-19, 2278👍, 0💬

Why are JSP pages the preferred API for creating a web-based client program?
Why are JSP pages the preferred API for creating a web-based client program? Because no plug-ins or security policy files are needed on the client systems(applet does). Also, JSP pages enable cleaner and more module application design because they provide a way to separate applications programming f...
2013-07-09, 2869👍, 0💬

What will be the default values of all the elements of an array defined as an instance variable?
What will be the default values of all the elements of an array defined as an instance variable? If the array is an array of primitive types, then all the elements of the array will be initialized to the default value corresponding to that primitive type. e.g. All the elements of an array of int wil...
2013-07-03, 2586👍, 0💬

What will be the output of the following statement? System.out.println ("1" + 3);
What will be the output of the following statement? System.out.println ("1" + 3); It will print 13.
2013-07-03, 3262👍, 0💬

Can main method be declared final?
Can main method be declared final? Yes, the main method can be declared final, in addition to being public static.
2013-07-02, 2618👍, 0💬

Can a public class MyClass be defined in a source file named YourClass.java?
Can a public class MyClass be defined in a source file named YourClass.java? No the source file name, if it contains a public class, must be the same as the public class name itself with a .java extension.
2013-07-02, 3027👍, 0💬

How many objects are created in the following piece of code?
How many objects are created in the following piece of code? MyClass c1, c2, c3; c1 = new MyClass (); c3 = new MyClass (); Only 2 objects are created, c1 and c3. The reference c2 is only declared and not initialized.
2013-07-01, 4802👍, 0💬

What is the default value of the local variables?
What is the default value of the local variables? The local variables are not initialized to any default value, neither primitives nor object references. If you try to use these variables without initializing them explicitly, the java compiler will not compile the code. It will complain abt the loca...
2013-07-01, 2415👍, 0💬

What are the different scopes for Java variables?
What are the different scopes for Java variables? The scope of a Java variable is determined by the context in which the variable is declared. Thus a java variable can have one of the three scopes at any given point in time. 1. Instance : - These are typical object level variables, they are initiali...
2013-06-28, 2350👍, 0💬

What will be the initial value of an object reference which is defined as an instance variable?
What will be the initial value of an object reference which is defined as an instance variable? The object references are all initialized to null in Java. However in order to do anything useful with these references, you must set them to a valid object, else you will get NullPointerExceptions everyw...
2013-06-28, 2554👍, 0💬

What happens if you dont initialize an instance variable of any of the primitive types in Java?
What happens if you dont initialize an instance variable of any of the primitive types in Java? Java by default initializes it to the default value for that primitive type. Thus an int will be initialized to 0, a boolean will be initialized to false.
2013-06-27, 2190👍, 0💬

Is exit a keyword in Java?
Is exit a keyword in Java? No. To exit a program explicitly you use exit method in System object.
2013-06-27, 2692👍, 0💬

Is delete a keyword in Java?
Is delete a keyword in Java? No, delete is not a keyword in Java. Java does not make use of explicit destructors the way C++ does.
2013-06-26, 2448👍, 0💬

Is next a keyword in Java?
Is next a keyword in Java? No, next is not a keyword.
2013-06-26, 3173👍, 0💬

Is main a keyword in Java?
Is main a keyword in Java? No, main is not a keyword in Java.
2013-06-25, 3000👍, 0💬

Is String a primitive data type in Java?
Is String a primitive data type in Java? No String is not a primitive data type in Java, even though it is one of the most extensively used object. Strings in Java are instances of String class defined in java.lang package.
2013-06-25, 2297👍, 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, 2235👍, 0💬

Is Empty .java file a valid source file?
Is Empty .java file a valid source file? Yes, an empty .java file is a perfectly valid source file.
2013-06-21, 3218👍, 0💬

What is the catch or declare rule for method declarations?
What is the catch or declare rule for method declarations? If a checked exception may be thrown within the body of a method, the method must either catch the exception or declare it in its throws clause.
2013-06-21, 3148👍, 0💬

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