I cannot figure this out for the life of me. I have a very simple piece of code that keeps terminating on the console window.
public class IsUnique {
public int add(){
return 4;
}
public static void main(String[] args){
IsUnique a = new IsUnique();
a.add();
}
}
public class IsUnique {
public int add(){
return 4;
}
public static void main(String[] args){
IsUnique a = new IsUnique();
a.add();
System.out.println(a);
// Wait until user hits key before quitting
System.in.read();
}
}
Related
code like this
for test two case
one is have volatile keywords ,can stop
other is without volatile,the thread infinite loop
public class VolatileTest extends Thread {
public boolean flag = false;
public static void main(String[] args) throws InterruptedException {
VolatileTest volatileTest = new VolatileTest();
volatileTest.start();
Thread.sleep(1000);
volatileTest.flag = true;
}
#Override
public void run() {
while (!flag) {
System.out.println("=====>");
}
}
}
My mistake. The problem is that you are calling a synchronized method inside your while loop. Try it like this. Stopped will never print unless you redeclare flag as volatile.
public class VolatileTest extends Thread {
public boolean flag = false;
public static void main(String[] args) throws InterruptedException {
VolatileTest volatileTest = new VolatileTest();
volatileTest.start();
Thread.sleep(1000);
volatileTest.flag = true;
System.out.println("flag is now " + flag);
}
#Override
public void run() {
int i = 0;
while (!flag) {
i++;
}
System.out.println("stopped");
}
}
public class positiveCount {
private static int countPositive(int[] elems) {
int positive = 0;
for (int i=0;i<elems.length;i++) {
if (elems[i] > 0){
positive++;
}
}
return positive;
}
//This gives me the number of the positive numbers.
public static void main(String[] args) {
}
}
in the main method, i want to enter a list, for example {3,4,5,-2,-3,0},how to call the method positveCount
If the main method is in the same class :
public static void main(String[] args) {
countPositive(new int[] {3,4,5,-2,-3,0});
}
Else (works also for case 1) :
public static void main(String[] args) {
PositiveCount.countPositive(new int[] {3,4,5,-2,-3,0});
}
My For loop is not working and my print statement (i) is showing error in eclipse
Following is the code.
public class For_Loop {
public static void main(String[] args) {
for (int i = 0; i < 10; i++);
System.out.println(i);
}
}
Remove the ; at end of for
public class For_Loop {
public static void main(String[] args) {
for (int i=0;i<10;i++){
System.out.println(i);
}
}
}
Please remove the semicolon from for loop.
public class For_Loop {
public static void main(String[] args) {
for (int i=0;i<10;i++)
System.out.println(i);
}
}
I do not understand why the output of this code is -10:
public class Prova {
public void sip(int i){
assert i>=0 : err();
System.out.println(i);
}
public int err(){
...
}
public static void main(String[] args) {
Prova t = new Prova();
t.sip(-10);
}
}
I thought assert would launch err();
Can i use the following code? It's not throwing any error at the Object but at obj.i. Is this a legal way of using an object? Also, how many ways can i create an object other than using the normal syntax obj s = new obj();
public class Test {
static int i;
static Test obj;
obj.i = 10; //am getting a compilation error here "Syntax error on token "i", VariableDeclaratorId expected after this token"
public static void main(String[] args) {
System.out.println(i+" "+ obj);
}
}
You need to place a static block around the obj.i assignment statement for this to work:
public class Test {
static int i;
static Test obj;
static { obj.i = 10; }
public static void main(String[] args) {
System.out.println(i+" "+ obj);
}
}
This is not, you didn't initialize. Furthermore you might not want to use static.
public static void main(String [] args) {
int i = 10;
Test obj = new Test();
obj.setI(i);
System.out.println("my objects I = "+ obj.getI());
}
now in your Test object
public class Test {
private int i;
public void setI(int i) {
this.i = i;
}
public int getI() {
return this.i;
}
}