Java Programming

Java heap is the heap size allocated to JVM applications which takes care of the new objects being created. If the objects being created exceed the heap size, it will throw an error saying memoryOutof Bound Java's default heap size limit is 128MB. If you need more than this, you should use the -Xms and -Xmx command line arguments when launching your program:

java -Xms -Xmx We can also give like in this format also.format is : -mx256m..Sometimes it will show error if you are using java -Xms -Xmx format..In that case use -mx256m this.value can be changed..

It really depends on the programming language, but in general, this is true. In Java, for example, the scope of a variable declared in a method is the method - outside of the method it is inaccessible, and once the method finishes execution, the variable disappears.

static variables are stored in a special area of the heap called the "permanent generation".

Vector is a type of collection object that Java has. Vector is a class that implements the AbstractList class and is often used as an alternative to arrays since it automatically extends the length of the list unlike arrays. A Vector can contain a collection of objects of any type. But it has fallen out of use due to the rise of the more convenient ArrayList class, but Vectors are still used for their security in multi threaded environment. Vectors are thread safe but array lists are not. An important fact to note is that Stack extends the Vector class.

Like this:

int sum = 0;

for(int i = 1; i<=100; i+=2){

sum+=i;

}

The "for" loop starts the counter i at 1, continues while it is less than or equal to 100, and increments it by 2 at a time.

Java is an object oriented programming language while Oracle is a Relational Database Management System. They are totally different and in no way similar to one another in terms of their features and abilities.

Oracle is also the name of the company which makes and sells the Oracle database. It also owns Java as a result of its acquisition of Sun Microsystems which created Java.

.class is the extension of a java byte code file.

Very simple example of an If statement checking a password just so you can see the syntax..



if (Password.equals("Password123"))
{
System.out.println("Welcome");
}
else
{
System.out.println("Incorrect Password");
}

Strings, which are widely used in Java programming, are a sequence of characters. In the Java programming language, strings are objects. The Java platform provides the String class to create and manipulate strings. Creating Strings The most direct way to create a string is to write: String greeting = "Hello world!"; In this case, "Hello world!" is a string literal-a series of characters in your code that is enclosed in double quotes. Whenever it encounters a string literal in your code, the compiler creates a String object with its value-in this case, Hello world!. As with any other object, you can create String objects by using the new keyword and a constructor. The String class has 11 constructors that allow you to provide the initial value of the string using different sources, such as an array of characters: char[] helloArray = { 'h', 'e', 'l', 'l', 'o', '.'}; String helloString = new String(helloArray); System.out.println(helloString); The last line of this code snippet displays hello. Note: The String class is immutable, so that once it is created a String object cannot be changed. The String class has a number of methods, some of which will be discussed below, that appear to modify strings. Since strings are immutable, what these methods really do is create and return a new string that contains the result of the operation.

All fields and methods of a class are inherited:

public class A

{private int x =10;public int XVal{get{return x;}}}

public class B:A

{public B(){x = 20;}}

Java is both compiled and interpreted.

At first, the Java source code (in .java files) is compiled into the so-called Bytecode (.class files). The Bytecode is a pre-compiled, platform independent version of your program. The .class files can be used on any operating system.

When the Java application is started, the Bytecode is interpreted by the Java Virtual Mashine. Because the Bytecode is pre-compiled, Java does not have the disadvantages of classical interpreted languages, like BASIC.

The only way that private attributes of a base class can be accessed by a derived class (protected or public) is through a protected or public method in the base class.

The protected or public method is the interface through which access to the attributes is defined and controlled.

I could make one, but "a program of zodiac signs" tells me little.

A do while loop is executed at least one time.

You may be reaching for "fraction".

The standard "Hello World" program in Java looks like:

class HelloWorld {

public void main(String[] args)

{

System.out.println("Hello World");

}

} //end class

A tokeniser splits a string into a number of smaller strings, called tokens.

For instance, a tokeniser might accept "one two three" and produce one, two, and three, discarding the intervening whitespace characters. Another might turn "(2+3)*foo" into (, 2, +, 3, ), *, and foo, splitting according to more complex rules.

A .jar file is just an archive (Java Archive) file. To see the files inside it you need to use a file compression utility to decompress the archive. you can use JAD to decompress the archive and get the stuff inside it.

Java source files have the .java extension, compiled Java class files have the .class extension.

Constructors have the same name as the class itself and they do not specify a return type, not even void because they return the instance of the class itself.

Because constructors have the same name as the class then they allow method overloading and also save memory and execution time of program.

Program release memory of constructors function after using this function and it reduce program complexity.