import java.io.*;
import java.util.List;
import java.util.ArrayList;
public class ListOfNumbers {
try
[code]....
i tried this code in BlueJ IDE.it told me i had an illegal beginning for "try".am i not supposed to use try for main methods?
I am trying to make a pyramid from blocks . I know that for example to make a bigger block from small blocks you write something like :
for(int i = 10 ;i <=1 ; i--){
for (int j= 10 ;j <= 1 ; j--) {
< statement to create block where you use both i and j to define the location of each block>
}
}
but i cant seem go grasp how to make a pyramid , so far my best effort is :
int i =10 ;
while (i >=1 ) {
for( ; i>=1 ; i-- ){
< statement to create block > }
}
At the moment visually i don't get a pyramid but it might be because of other issues and not because of the while and then a for inside it approach .
My approach is correct and if now what would be the correct one to create a pyramid from smaller blocks ?
What static initialization blocks do in java?
View Replies View RelatedI'm reading the following section of the Oracle docs:
Guarded Blocks (The Java Tutorials > Essential Classes > Concurrency)
We have multiple threads. One of them sets the joy flag to true. The other waits until joy flag is set to true in order to print to the output stream. Rather than squander processer resources with a while loop, we choose to use the wait method of Object which suspends execution of thread. When the other thread throws an exception, we check the loop condition again.
Java Code:
public synchronized void guardedJoy() {
// This guard only loops once for each special event, which may not
// be the event we're waiting for.
while(!joy) {
try {
wait();
} catch (InterruptedException e) {}
}
System.out.println("Joy and efficiency have been achieved!");
} mh_sh_highlight_all('java');
The documentation goes on to state the following:
When a thread invokes d.wait, it must own the intrinsic lock for d - otherwise an error is thrown. Invoking wait inside a synchronized method is a simple way to acquire the intrinsic lock. When wait is invoked, the thread releases the lock and suspends execution.
The statement seems somewhat contradictory. When we invoke wait inside a synchronized method, is the intrinsic lock acquired or released? I thought it was the synchronized keyword itself that acquired the intrinsic lock.
When I run this (entering 12 for both questions) I get this error:
java.lang.ArrayIndexOutOfBoundsException: 12
at MathTablesTwo.main(MathTablesTwo.java:22)
Also, what would be the proper way to organize my code into blocks?
import java.util.Scanner;
public class MathTablesTwo {
public static void main(String args[]) {
Scanner input = new Scanner(System.in);
[code]....
when do they get called?
from my code
class MyJava{
static { System.out.println("initializing..."); }
public static void main(String[] args)
{
}
}
i did get the "initializing..." string output, even though i didn't create any MyJava objects.
from this fact, i inferred that initializing blocks get called once when the program compiles.
am i right?
I've already seen large code blocks inside JSP's, in a way it is very hard to maintain the web application. Is there a way to avoid that?
View Replies View RelatedI have to divide a text file into blocks of 128 bits. I think i must use the ByteArrayInputStream and ByteArrayOutputStream classes. is there any website showing how to user these two ByteArrayInputStream and ByteArrayOutputStream classes in detail. or it would be much better if you could show me a portion of the code.
View Replies View RelatedI have a program where I have to open a file and then run a piece of code to do something with it. However since there are different files I want to run different pieces of code depending on the file. I have a JFileChooser setup and it works but I would like to have a something like an if else depending on the file extension.
View Replies View RelatedI have to write a program that will read a picture and then print out the number of blocks inside it.
I have to read the picture as a binary matrix of the size r - c (number of rows times number of columns). The blocks are groups of one or more adjacent elements with the value 1.
- Blocks are built exclusively of elements with value 1
- Each element with value 1 is a part of some block
- Adjacent elements with value 1 belong to the same molecule.
We only take into account the horizontal and vertical adjacency but not diagonal.
INPUT:
In the first line of the input we have the integers r and c, separated with one space.
Then we have the r lines, where each contains s 0's and 1's.
The numbers inside the individual lines are NOT separated by spaces.
The OUTPUT only print the number of blocks in the picture.
Example:
INPUT:
7 5
01000
00010
00000
10000
01000
00001
00100
OUTPUT:
6
THIS IS WHAT I CAME UP SO FAR:
import java.util.Scanner;
class Blocks{
public static void main(String[] args){
Scanner sc=new Scanner(System.in);
char ch[][];
int rowNum=sc.nextInt();
int columnNum=sc.nextInt();
[Code] ....
We have triangle made of blocks. The topmost row has 1 block, the next row down has 2 blocks, the next row has 3 blocks, and so on. Compute recursively (no loops or multiplication) the total number of blocks in such a triangle with the given number of rows.
triangle(0) → 0
triangle(1) → 1
triangle(2) → 3
what is different between void main() and public void main()
View Replies View RelatedI'm trying to make a TBG (Text Based Game) in Java for Android. Now, when I try to run it, it says No Main Method to run this program. The compiler also checks the program and tell me there are no errors.
View Replies View RelatedWhy we do not need main in applet .....
View Replies View RelatedWhat happened when we use main() as a private. . . . .???????
View Replies View RelatedI've made a class called Car with a method which will tell me a category for the engine size regarding the actual size (which I've included in the main just so I could see if it works) but everytime I test it I get an error.
public class Car {
public String b;
public String c;
public double es;
public double cs;
public String getCategory() {
if (es < 1.3)
[Code] ....
Figured it out. Was missing parenthesis on audiCar.getCategory();
in java why main method is always static in nature...
View Replies View RelatedI am writing a code where in the first method the question will ask whats your favorite website. for example www.javaprogrammingforums.com...when it outputs it will read just "javaprogrammingforums" without the www. and the .com.
Because the program will ask a series of questions in the main, I would like website question to be returned to the main. Here is my code, and what can I do?
import java.util.Scanner;
public class chapter3 {
public static String website(Scanner kb) {
String website;
System.out.println("What is your favorite website?");
website = kb.next();
[Code] ......
How do I call a class within the main. For example, this is what i have in my code right now. I am trying to call the class BlackJackGame.
package blackjack;
public class BlackJack {
public BlackJack() {
BlackJackGame();
}
}
public static void main(String[] args) {
Scanner kb = new Scanner(System.in);
int hours = getHours(kb);
char major = getMajor(kb);
[code]....
I'm trying to return a char c,o, or x if that is their "major code" that the scanner grabbed.
I have 3 source file below
//Hello.java
public interface Hello {
public void sayHello();
}
//Espanol.java
public class Espanol implements Hello {
[Code] ....
The idea is to create a program to add plants and retrieve plants from a Nursery. I created a class with the properties of the plants and also there is the class an Array list to keep track of the plants entered ( they will have to be printed later) (I am not too sure if adding a public class there is the best option.
The program will allow the user to pick and action and from there the code will do something. I don't want to have all the code inside 'main' The problem is in line 114.This is what I have so far.
Java Code:
package plant.nursery;
import java.util.ArrayList;
import java.util.Scanner;
/**Class to create a plant for a nursery.
public class PlantNursery
[code]....
this is my program error occured run time,but compile sucessfully
{error msg-Error: Main method not found in class helloworldapp.HelloWorldApp, please define the main method as:
public static void main(String[] args)}
class HelloWorldApp
{
private int empno;
private float salary;
void setHelloWorldApp()
{
empno=12;
salary=1200;
[code]....
How do I call a class within the main. For example, this is what i have in my code right now. I am trying to call the class BlackJackGame.
package blackjack
public class BlackJack {
public BlackJack() {
BlackJackGame();
}
}
For some reason when I try to run the program it gives me an "editor does not contain a main type" launch error.
/*
* A program that plays and scores a round of the game Poker Dice. In this game, five dice are rolled. The player is allowed to select a number of those five dice to re-roll. The dice are re-rolled and then scored as if they were a poker hand. The following hands MUST be scored in this assignment:
* * High card
* * One Pair
* * Two Pair
* * Three of a Kind
* * Full House
* * Four of a Kind
* * Five of a Kind
* For extra credit, you may also implement:
* * Straight
*/
import java.util.Scanner;
public class Project10 {
public static void main(String[] args) {
Scanner inScanner = new Scanner(System.in);
int[] dice = new int[5];
resetDice(dice);
System.out.print("Your current dice: + dice");
[code]....
I keep getting a zero dollar return when I run my main. I am multiplying grossPay by hours but something is not catching.
public class employee {
private String name; //employees name
private int id; //employees id number
[Code].....