Develop Reference

How to fix error while installing NetBeans?

I have installed Java and am trying to install NetBeans 11.3 on my Windows 10 but after I ran the exe. installer, an error message popped up:
An unexpected exception happened in thread main
java.lang.NoClassDefFoundError java/util/jar/Pack200

NetBeans have problems with the jdk-14, because I suppose that you have install the jdk-14 so uninstall it and try it with the jdk-13.0.2.

Sorry, but in my opinion is to install an old version from Java no solution, just because it works. When someone has problems with his Firewall, simply disable the Firewall would also be no solution.
https://www.java.com/en/download/faq/other_jreversions.xml
We highly recommend users remove all older versions of Java from your
system. Keeping old and unsupported versions of Java on your system
presents a serious security risk. Removing older versions of Java from
your system ensures that Java applications will run with the most
up-to-date security and performance improvements on your system.
The "real" solution would be a reprogramming of the NetBeans installer.
This used function was suggested for deprecated on 2018-04-04, which was done on 2018-08-23.
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8200752
The removal was suggested on 2019-10-08, which was done on 2019-12-18.
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8232022
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=JDK-8232022
We assume that developers who rely on Pack200 have had enough notice about its proposed removal to make alternative arrangements. … We assume that developers who use pack200 to shrink application JARs can switch to either the jlink tool or the jpackage tool to create application-specific runtimes with an optimized form factor.
edit: I solved it this way.
uninstalled JDK 14
installed JDK 13.0.2
installed Apache NetBeans
installed JDK 14
open C:\Program Files\NetBeans\netbeans\etc\netbeans.conf and changed path to JDK
uninstalled JDK 13.0.2
Now NetBeans runs with the JDK 14.

Yes, I got it working as follows from cmd, when referring to older version:
Apache-NetBeans-11.3-bin-windows-x64.exe --javahome "C:\Program Files\Java\jdk-12.0.2"

The https://netbeans.apache.org/download/nb113/nb113.html site now has this
memo:
The installers will not run under JDK 14 because usage is made of the Pack200 Tools and API, for packing and unpacking, which is removed in JDK 14, see JEP 367.

If several JDK versions are installed, then you need to define the environment variable "JAVA_HOME" where to set the path to JDK-12.
Details are described here. (Only in Russian)

An alternate way to Andy's.
(Windows)
1) Right click on "Apache-NetBeans-11.3-bin-windows-x64" installer and select "Create shortcut".
2) Right click on the created shortcut and select "Properties".
3) In the "target" textbox, add your under 14 JDK version path at the end, here is how mine looks like:
C:\Users\userfoldername\Desktop\Apache-NetBeans-11.3-bin-windows-x64.exe --javahome "C:\Program Files\Java\jdk-13"
4) Press Ok when done, double-click on the shortcut and it should install fine now.

Switching to openJDK 12 worked for me too. But instead of uninstalling JDKs or manually changing the env, I use Sdkman.io which works like Node version manager if you have used that. It manages your JDKS for you and offers downloads of different versions (Open, Zulu, Graals) and will switch between them with with just a quick command.

I found a nice solution in 3 steps:
check all versions of the JDK path in Environment variables, if there is an outdated path please remove it and keep the latest version of the Java JDK bin path.
after the second step, please uninstall the Netbeans and re-install the latest version.
Netbeans will found the latest JDK path in case it was jdk14 and choose JDK latest version path for NetBeans.
solved

Just install JRE from oracle. Everthing will run fine. I have the same issue

Can't download JDK 8

I'm trying to setup Unity to build for Android. But I can't get the Java Development Kit. Can't download it and can't find it either.
In this answer, the guy says
To ensure JDK is installed, just go through the following :
press Win + R
type 'cmd' in the popup and press button OK.
in the console which has opened, type javac -version and press enter.
You should see as an output :
javac 1.8.0_XX
If so SDK is installed.
I did that and I got "javac 1.8.0_XX", and so I assumed I had the JDK, so I went to Unity > External Tools > JDK and tried linking the following path: "C:\Program Files\Java\jre1.8.0", and got the error message: "The path you specified does not look like a valid JDK installation. Android development requires at least JDK(1.7), having JRE only is not enough. Please make sure you are selecting a suitable JDK home directory or download and install the latest JDK: link"
I clicked the download link for windows x64 and it never loads and eventually says there's no connection. I tried the x86 as well.
In this SO question How do I find where JDK is installed on my windows machine?
Answer: For windows, in the command prompt:
c:\> for %i in (java.exe) do #echo. %~$PATH:i
And so I did that and got the path "C:\ProgramData\Oracle\Java\javapath\java.exe"
When I try linking via Unity > External tools > JDK it doesn't find any files.
I'm a bit clueless now.

#RealAnyOne, you have installed Java with JRE only installation i.e., without out a JDK that’s what you see only one folder and this is why it also showing version in the command line since it won’t check for JDK. JRE is Java Runtime Environment, JDK is Java Development Kit which contains many essential libraries. So Ideally there should be two folders JRE and JDK. This is the reason you are getting this issue with Unity.
To Fix::
Uninstall old Java 8
Download Java 8 from the oracle website
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
Install it. Now you should have two folders. Then point your Unity to it.

Java program Not running in Eclipse [duplicate]

I'm trying to install Java to use Eclipse (I followed all instructions to install Java and Eclipse) but my Eclipse is not starting due to some bad configuration I guess. I can't figure out why it's not working for me.
Eclipse Installation:
Extracted Eclipse at C:\eclipse
Created a shortcut to my desktop having target C:\eclipse\eclipse.exe
When I try to run Eclipse with this shortcut, I see following Eclipse splash screen for a second and it disappears. Eclipse does not start at all.
JAVA Installation:
Installed JDK at C:\Program Files\Java\jdk1.7.0_10
Installed JRE at C:\Program Files\Java\jre7
Environment Variables Configuration:
JAVA_HOME = C:\Program Files\Java\jdk1.7.0_10
PATH = C:\Program Files\Java\jdk1.7.0_10\bin;
I tested my Java installation using the console and figured out this issue but I don't know how to fix it, and I guess this is causing Eclipse not to start.
Problem:

Go to Eclipse folder, locate eclipse.ini file, add following entry (before -vmargs if present):
-vm
C:\Program Files\Java\jdk1.7.0_10\bin\javaw.exe
Save file and execute eclipse.exe.

please try to execute java from
C:\Program Files\Java\jdk1.7.0_10\bin
i.e from the location where java is installed.
If it is successful, it means that the error lies somewhere in the classpath.
Also, this guy seems to have had the same problem as yours, check it out

Check that downloaded eclipse/JDK/JRE is compatible with your processor/OS architecture that is are they 32bit or 64bit?

Not able to run Appium {“message”:”A new session could not be created. (Original error: ‘java -version’ failed
I used Jdk 1.8 and JRE 1.8, Classpath is also set properly but I observed that Java command gives Error to initialization of VM (java/lang/NoClassDefFoundError: java/lang/Object)
Solution:
Uninstalled JRE and JDK completely
Installed JRE 1.8 then
Installed JDK 1.8
Set Classpath
check Java command works or not and its working
also able to execute the Appium program thru Eclipse Kepler Service Release 2 with JDK1.8 support

I had the same error in my case was when I needed to update jdk 7 to jdk 8, and my bad was just I installed jdk8 and I never installed jre8, only that, the error was solved immediately when I installed jre8.

Try placing the desired java directory in PATH before not needed java directories in your PATH.

I had the same issue on Windows 7 and I had to install both JDK and JRE and it's a success.

I faced the same problem,Eclipse splash screen for a second and it disappears.Then i noticed due to auto update of java there are two java version installed in my system. when i uninstalled one eclipse started working.
Thanks you..

I've observed this with STS and Eclipse and running java from CMD too on Windows 7/8/10 and following was my simple solution:
Actually, when I installed JDK 8 and STS/Eclipse it created one directory i.e. C:\ProgramData\Oracle\Java\javapath with the following files:
C:\ProgramData\Oracle\Java\javapath\java.exe
C:\ProgramData\Oracle\Java\javapath\javaw.exe
C:\ProgramData\Oracle\Java\javapath\javaws.exe
Along with that, it appended Path Environment variable of System with this location C:\ProgramData\Oracle\Java\javapath
I've just removed above entry from Path Environment variable of System and added the location of the actual JDK instead i.e. C:\Program Files\Java\jdk1.8.0_131\bin
Now that is not necessary to add that -vm option in eclipse.ini or
SpringToolSuite4.ini either.

I just spent about 1 hour to figure out possible solution for the same error.
So what I did under MS WIndows 7 is following
Uninstall all Java packages of all versions.
Download last packages Java SE or JRE for your 32 or 64 Windows and install it.
First install JRE and second is Java SE.
Open text editor and paste this code.
public class Hello {
public static void main(String[] args) {
System.out.println("test");
}
}
Save it like Hello.java
Go to Console and compile it like
javac Hello.java
Execute the code like
java Hello
Should be no error.

sometime you missed some file like I missed my one file rt.java
so better to check yours .........
C:\Program Files\Java\jdk1.8.0_112\jre\lib

0
I just spent about 1 hour to figure out possible solution for the
same error.
So what I did under MS WIndows 7 is following
Uninstall all Java packages of all versions.
Download last packages Java SE or JRE for your 32 or 64 Windows and
install it.
First install JRE and second is Java SE.
List item

Below error is thrown when there are multiple versions of jdk on your machine:
error occurred during initialization of VM
java/lang/NoClassDefFoundError: java/lang/Object
so for this Just use below:
set PATH="JDK bin path" in cmd

I had a same issuse, my file location was in D-drive, and then i shifted to the c-Drive and it works.

Possible bug in Java Web Start

I am using Ubuntu operating system with Java version 1.7.0_15 (Iced Tea). I am unable to access the Java web start application. Every time I start it I get message that Java web start requesting JRE 1.7 and then says that it is unable to install so manually install and then it failed to install the JRE. I do not know what to do.
Here is my java version
Here is few important information
1. I have validated JNLP file using JaNeLa and there is no error.
2. Ubuntu is opening Application with JRE 1.6 perfectly fine.
3. On Windows every version is running perfectly fine.
4. I have tried with deployment tool kit but the always redirect me to the Sun page to download the linux version of JRE and even after installing that it again redirect me to the download page.
Please let me know if I can provide more information.

So finally after working whole day I have found the problem with my system. I am not sure why my question got -3 but it was valid question. The problem was with the Java plugin in the Firefox browser. Although I have installed jdk 7 on my machine but the firefox plugin was still pointing to the jre6 so giving error. So I have to manually create the link for the jre 7 in my machine
ln -s /usr/lib/jvm/<<location of jre 7>>/jre/lib/i386/libnpjp2.so ~/.mozzilla/plugins
Then I restarted the browser and make sure that I have the latest plugin and it started working, So it was not the java installed but it was firefox plugin.
Just FYI, oracle has stopped it support for java plugin for linux due to some licensing so you have to install it manually. Thanks
You can check the installed plug-in by typing 'about:plugins' in your address bar of firefox

IMHO OpenJDK 7 is not a JRE 7.
You may uninstall it before install oracle jre. Otherwise you have to use sudo update-alternatives to define the default java version
See https://askubuntu.com/questions/67909/how-do-i-install-oracle-jdk-6

Compile Java 1.5 web app in Netbeans on Mac OSX 10.7.5

I am running Netbeans on my Mac OSX 10.7.5 which uses Java 1.6. I need to compile my web app in Netbeans against Java 1.5. I tried to install Java 1.5 on my Mac OSX, but it will not let you. How can I compile my netbeans web app against Java 1.5 on my mac osx?

Go to Tools -> Java Platforms. There, click on Add Platform, point it to YOUR_JDK_LOCATION. You can either set the another JDK version or remove existing versions.
after adding multiple platform change your project compile specification according to your requirement
To download jdk binary please visit below location
Link 1 zip file
Link 2 tar file

change your java version
$ export JAVA_HOME=/usr/libexec/java_home -v '1.5*'`
OR
parameterize the compiler like javac -source 1.5 -target 1.5

I believe I figured it out. In Netbeans, if you right click your project and go to 'Properties', in the 'Sources' category there is an option that says 'Source/Binary Format' which contains a drop down list where you can select the JDK version to build your project.
Since I am running JDK 6 on my mac, it will allow you to select version 6 and below, and in my case, I select version 5.