Java Programming

You double-click on it.

You can indeed launch a jar file from the command line, with the following command:

java -jar yourfile.jar

As well as this you can assign "Jar Launcher" as the default app. to use when you double-click a jar file, as follows (I don't believe you need the developer tools installed for this):

Click once on the .jar file in the Finder and then from the menubar in the Finder select File -> Get Info". Click on "Open with" and from the popup menu select "Other". A file browser window will open. In this window, go to the /System/Library/CoreServices folder and select 'Jar Launcher'. Then make sure the "Always Open With" checkbox is checked and then click Add. Then click the "Change all" button so that any jar file will be opened automatically. Finally, close the Info window and now when you double-click any of your jar files they should run automatically.

In Java toUppercase() is a method of the class String: https://docs.oracle.com/javase/7/docs/api/java/lang/String.html#toUpperCase()

The two primary methods of programming are procedural and object-oriented.

An input stream is a character sequence device or buffer from which input can be gathered. The standard input stream is usually a keyboard, data file or the output stream from another program. The user of the program can normally decide where standard input may be redirected from when launching the program, typically defaulting to the keyboard.

Suppose you assume that a number passed into a method (say, methodOne()) will never be negative. While testing and debugging, you want to validate your assumption, but you don't want to have to strip out print statements, runtime exception handlers, or if/else tests when you're done with development. But leaving any of those in is, at the least, a performance hit. Assertions to the rescue!

Assertions work quite simply. You always assert that something is true. If it is, no problem. Code keeps running. But if your assertion turns out to be wrong (false), then a AssertionError is thrown right then and there, so you can fix whatever logic flaw led to the problem. Assertions come in two flavors: really simple and simple, as follows: Really simple: private void doSomething() { assert (y > x); // more code assuming y is greater than x } Simple: private void doSomething() { assert (y > x): "y is " + y + " x is " + x; // more code assuming y is greater than x }

Base class should no knowledge about derived classes.

The "private" modifier on a data member means private to the class which defined it. Base class cannot directly reference/access the private data member of the derived class, and the derived classes cannot access the private data member defined in the base class.

Either way the accessing the private data member should be done via properties or getters

#include <stdio.h>

int main()

{

int number, temp;

printf("enter the number");

scanf("%d",&number);

printf("\n reverse of %d",number);

while(number>0)

{

temp=temp*10+number%10;

number=number/10;

}

printf(" is %d",temp);

}

public class Address

{

System.out.println(" The Address of Study Center is A-135, Model town")

}

String a=" Suraj ";

String t=a.trim();

this will remove all the leading and trailing white spaces

The class case exception is thrown when an object A of class type B is cast to a class type C where C is neither B nor its subclass.

• Abstraction: One point of confusion regarding abstraction is its use as both process and an entity. Abstraction, as a process, denotes the extracting of the essential details about an item, or a group of items, while ignoring the inessential details. Abstraction, as an entity, denotes a model, a view, or some other focused representation for an actual item.
• Information Hiding: Its interface or definition was chosen to reveal as little as possible about its inner workings."
  • Why confusing: Abstraction can be used as a technique for idenfying which information should be hidden. Confusion can occur when people fail to distinguish between the hiding information, and a technique(e.g., abstraction) that is used to help identify which information is to be hidden.

Almost all controls' ActionListener triggers the actionPerformed upon the enter key press == == Using an anonymous class implementation:

Component c; // this is the component you want to add a listener to

c.addKeyListener(new KeyListener() {

public void keyPressed(KeyEvent e) {

if(e.getKeyChar() == e.VK_ENTER) {

// put the code you want to execute when Enter is pressed here

System.out.println("ENTER PRESSED");

}

}

// unused abstract methods

public void keyTyped(KeyEvent e) {}

public void keyReleased(KeyEvent e) {}

});

please clarify the question. I have a feeling that the question is not asking what I am about to answer here.

You may have a class named "main" in the program.

I presume non-main means any class that is not main.

Can an object be created from a class (named main or non-main)? It depends on how you design that class. Ususally yes.

OLE Object

a variable holds a single type of literal. i.e. 1, bat, 345. A object is a instance of a class created by the a programmer with a set of methods which preforms certain task depending what methods have been defined.

int a = 4; // a would be the variable

Car b = new Car();// b is an object

b.carGo();// this is an method in the object car created below.

class Car(){

void carGo(){

car moves;

}

}

Depends on the language. For Java, yes.

In Java:

You declare the variable like this:

int sum;

If you want to include decimals, change this to:

double sum;

To store an initial value, just use the assignment operator:

sum = 0;

You can combine this with the declaration:

double sum = 0.0;

To add something to the variable, for example the value of a variable called "x", use one of the following:

sum = sum + x;
sum += x;

In Java:

You declare the variable like this:

int sum;

If you want to include decimals, change this to:

double sum;

To store an initial value, just use the assignment operator:

sum = 0;

You can combine this with the declaration:

double sum = 0.0;

To add something to the variable, for example the value of a variable called "x", use one of the following:

sum = sum + x;
sum += x;

In Java:

You declare the variable like this:

int sum;

If you want to include decimals, change this to:

double sum;

To store an initial value, just use the assignment operator:

sum = 0;

You can combine this with the declaration:

double sum = 0.0;

To add something to the variable, for example the value of a variable called "x", use one of the following:

sum = sum + x;
sum += x;

In Java:

You declare the variable like this:

int sum;

If you want to include decimals, change this to:

double sum;

To store an initial value, just use the assignment operator:

sum = 0;

You can combine this with the declaration:

double sum = 0.0;

To add something to the variable, for example the value of a variable called "x", use one of the following:

sum = sum + x;
sum += x;

import java.awt.*;

import java.applet.*;

public class barChart extends Applet {

String label[];

int values[];

int n = 0;

public void init() {

try {

n = Integer.parseInt(getParameter("cols"));

label = new String[n];

values = new int[n];

label[0] = getParameter("label1");

label[1] = getParameter("label2");

label[2] = getParameter("label3");

label[3] = getParameter("label4");

values[0] = Integer.parseInt(getParameter("values1"));

values[1] = Integer.parseInt(getParameter("values2"));

values[2] = Integer.parseInt(getParameter("values3"));

values[3] = Integer.parseInt(getParameter("values4"));

} catch (NumberFormatException e) {

}

}

public void paint(Graphics g) {

g.setColor(Color.red);

for (int i = 0; i < n; i++) {

g.drawString(label[i], 100, 100 + i * 50);

g.fillRect(150, 80 + i * 50, values[i], 40);

}

}

}

<html>

<body>

<applet code="barChart.class" height="700" width="700">

<param name="cols" value="4" />

<param name="label1" value="1994" />

<param name="label2" value="1995" />

<param name="label3" value="1996" />

<param name="label4" value="1997" />

<param name="values1" value="110" />

<param name="values2" value="100" />

<param name="values3" value="190" />

<param name="values4" value="140" />

</applet>

</body>

</html>

There are two types of languages. Procedure oriented language and object oriented langugae.

An object oriented langugae is quite impresses from real world environment. it says that for example a classroom is full with chairs then that class is a class of object oriented and those chairs are object...

Basically this makes programing very easy and short...

Hope this answer was of some help...

SEK class Μα was created in 1953.

select the list and choos ethr drop down arrow next to the bullets button to selcet the bullets library

Command Line Interface