I am a beginner studying Java using NetBeans. I created my first class and some simple code:
public class suju {
public static void main(String[] args){
System.out.print("hello word");
}
}
Why don't I see any result when I click run? I am supposed to see hello world but nothing like this is shown.
Only a message BUILD SUCCESSFUL (total time: 0 seconds)
Unfortunately, I can't post images yet to better present the problem I am facing.
Try to right click on the class file on the left panel then choose run option
Mine was doing the same.
I went to java.com and downloaded java again- it then prompted me to uninstall all out-if-date updates.
When I ran it again it was working.
Related
Here is the code that's expected to produce error:
public class App {
public static void main (String[] args) {
tick();
}
public static void tick () {
System.out.print("hi");
Note that the closing angled bracket of both, the method tick() and class App is missing. Although the IDE indicates this error while writing code, this compiles and runs just fine. It doesn't look like an issue with Java (or my OS) as doing javac in the command line surely does fail.
What's even funnier...the following code throws a Runtime exception after successfully executing tick():
public class App {
public static void main (String[] args) {
tick();
public static void tick () {
System.out.print("hello..");
Here I skipped closing bracket of main too.
I have installed the development version of Netbeans that has support for Java 9.
[This is a comment more than an answer, but I wanted to include screen shots to show that I cannot reproduce either issue.]
An interesting problem. I just downloaded the most recent nightly build (NetBeans Dev 201803060002) and built your code using Oracle JDK 9.04.
Neither of your code examples would compile for me. For the first example the error for the final line was "reached end of file while parsing System.out.print("hi");". Here is a screen shot:
For the second example, where you removed the closing bracker of main() the additional error reported was "illegal start of expression public static void tick () {":
I suggest that you try the following:
Create a new project and new class "App2" to see if you can replicate the issue with that same version of NetBeans.
If you cannot then review why App compiles and App2 does not.
If you can replicate the problem then download the most recently nightly build to see if you can still replicate the problem (i.e. Invalid source code compiles cleanly). If you cannot then I don't think it is worth raising a bug report or spending further time on the matter.
However, if you can replicate the problem then by all means raise a bug report. But I strongly recommend being able to replicate the failure before doing that. Otherwise you are likely to get a WORKSFORME response if the NetBeans team cannot replicate the issue.
One more thing: it would be helpful to update your OP with the stack trace for that RuntimeException, which you should also include in your bug report.
Ah...I see it now. At some point of time I checked the "Always run without asking" checkbox and since then my IDE is ignoring all the compile time errors without any warnings.
Sorry guys...my bad.
Out of nowhere when I run my application no GUI pops up only says BUILD SUCCESSFUL (total time: 1 second) in the console, don't know why it happened or if anyone has had this before? Tried restarting netbeans etc ill post my code below incase its that. And it was working at one point.
pastebin(dot)com/XvD30sCP code is here
public static void main(String args[]) {
global_crime gc = new global_crime();
gc.setVisible(true);
}
Add this... it will work now..
Eclipse give error when I try to compile and run to JAVA codes. The error is
"The selection cannot be launched, and there are no recent launches".
How to fix this issue ??
your code is wrong. you need a main method to launch your program
package main;
public class main {
public static void main (String[] args) {
System.out.println("Test");
}
}
Note: The name of the class always has to be the name of the file, and typically java classes start with an uppercase letter
I think you should run main first and describe your problem in more detail if you still have a problem.
Q: When I try to run my project by clicking the green "Play" button, I get an error of, "The Selection cannot be launched, and there are no recent launches."
A: See previous question. You must run your project's "Main" class at least once by using the right-click method described above, before the "Play button" to run a project will work.
http://courses.cs.washington.edu/courses/cse143/15wi/eclipse_tutorial/faq.shtml
I have an error in my first step with Java, so when i try to run the code hello world:
class apples{
public static void main(String args[]){
System.out.println("Hello World!");
}
}
I go to: - Run as .. -> Then i choose Java aplicacion - > And i press Ok
But when i press Ok does not appear the window down to show me the correct message Hello World
Your code works fine for me:
class apples
{
public static void main(String args[])
{
System.out.println("Hello World!");
}
}
I downloaded it to c:\temp\apples.java.
Here's how I compiled and ran it:
C:\temp>javac -cp . apples.java
C:\temp>dir apples
Volume in drive C is HP_PAVILION
Volume Serial Number is 0200-EE0C
Directory of C:\temp
C:\temp>dir ap*
Volume in drive C is HP_PAVILION
Volume Serial Number is 0200-EE0C
Directory of C:\temp
08/15/2010 09:15 PM 418 apples.class
08/15/2010 09:15 PM 123 apples.java
2 File(s) 541 bytes
0 Dir(s) 107,868,696,576 bytes free
C:\temp>java -cp . apples
Hello World!
C:\temp>
Your lack of understanding and the IDE appear to be impeding your progress. Do simple things without the IDE for a while until you get the hang of it. A command shell and a text editor will be sufficient.
Sorry about missing javac; cut & paste error.
If you look at the screenshot, your class name is there, last in the list. Select it and press OK. To not see this message again, right-click on the class name on the left side and select there Run...->Java Application.
The only problem that causes your error here is that the classname and the filename do not match - and they have to.
Solution
Rename either the file thesame.java to apple.java or the class to thesame. Then if you select "Run as..." again, eclipse will present a menu item to start your Java application.
(other mentioned, that there's no requirement that a top-level class and the filename do match - unless the top level class is public. Of course this is true. But the problem was about "running" a class under eclipse as a Java application)
Try public class apples and make sure the file is apples.java. Also it should be public static void main(String[] args)
You have 2 classes by name of "thesame.java" under the source folder. Since one is directly under the src folder, and other under (default package), they use the same namespace, hence Interpreter is confused which java file to execute and is asking you to select the class you want to execute.
Class names must be capitalized... so change apples to Apples. Also, if you are a beginner (which it seems like), I would recommend the Netbeans IDE -- it's a bit more friendlier for new users than Eclipse.
You class must be named "thesame" if you store it in a file called "thesame.java", as you have. Either rename your class to "thesame" or change the file to be "apples.java".
You should move the "[]" to be before "args". So, String[] args.
Either select "apples" at the bottom of the menu you posted and run it, or right-click on the Java file and make it the default thing to run for this project. Or launch it by right-clicking on the file and selecting "run".
This is my first post on the forum, hope all of you guys are well.
I've got a issue using JiST/SWANS, the ad hoc simulator in java within eclipse.
I managed to load the API, (as an external JAR ofcourse) but Im basically having a problem integrating the runtime of JiST within eclipse.
After running the hello world im usually getting a stackoverflowerror exception, since it may need modifications within the runtime.
import jist.runtime.JistAPI;
public class hello implements JistAPI.Entity {
/**
* #param args
*/
public static void main(String[] args) {
System.out.println("simulation start");
hello t = new hello();
t.myEvent();
}
public void myEvent()
{
JistAPI.sleep(1);
myEvent();
System.out.println("hello world, t=" + JistAPI.getTime());
}
}
the website is: http://jist.ece.cornell.edu/index.html
Thank you in advance!
Actually you need to run Main.java within jist.runtime. But before rigth click Main.java, properties, Run/Debug settings, New,Arguments and type your class name (plain name no .java needed) in Progam arguments. This will tell the jist interface to translate your code using the rewriter and run it.
Examples:
To run hello.java type "hello"
To run aodvsim.java type: "jist.swans.Main driver.aodvsim"
If there are arguments needed type them after the clas name like: "jist.swans.Main driver.aodvsim -n 25 -f 2000x2000 -a grid:5x5 -t 10,600,60"
Wilmer Arellano
How well does SWANS work? Given that the documentation and code date back to 2005, I am not sure if this is the best platform to use.