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i'm using Netbeans on Ubuntu, when i write top command i notice that Java causes like 100%+ cpu usage. Is there anything to do to speed up Netbeans ? can i download another JRE on ubuntu to speed it up (i'm using OpenJDK).
Thanks .
Another item that helps me, apart from replacing OpenJDK with SunJDK is the "Scanning Sources" which can be disabled if you goto Tools -> Options -> Misc -> Files and uncheck the Enable "auto-scanning" of sources.
I am not 100% sure what that option does, but it speeds up my projects. Also I would try NetBeans 7, they have made massive leaps and bounds in the newer versions from the older (not knowing what version you are using).
Yes, it's well known that Netbeans runs slower with OpenJDK.
Your question has been answered on AskUbuntu before:
https://askubuntu.com/questions/5567/how-to-install-the-sun-java-jdk
Enable the partner repository and then install Sun Java with:
sudo apt-get install sun-java6-jdk
I would:
Replace OpenJDK with Sun's JDK. OpenJDK's performance is still not upto par.
I would read this (a bit dated, but most of works with some changes).
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I have JDK 8 installed in my ubuntu 18.04 system and I now want to upgrade it to JDK 11 using this. I just want to know if this would create any problem or not. Would the older version be removed on upgrading( Actually I want older version to be removed by itself)?
Do this to uninstall previous versions of openJDK on Ubuntu
sudo apt-get remove openjdk
To remove all of the config files and dependencies.
sudo apt-get purge --auto-remove openjdk*
Then install openJDK 11
sudo apt-get install openjdk-11-jdk
An upgrade will generally allow code compiled for Java 8 to run; but, there are some caveats.
The inclusion of Project JigSaw means that the access rules for "reaching" a method have changed slightly. They are almost compatible between Java 8 and Java 11. The differences will show when:
You try to use one of the com.sun.* packages (or any other non-public api entry point).
You try to use reflection on a non-public API entry point.
You alter the launch to use a module, which will deactivate the Java 8 "default" module handling.
In short, it's almost an easy upgrade. The problems come into play when code is doing something it shouldn't have done, or when you have code not designed for modules, and some of your runtime code is designed for modules.
If you have access to source code, you can fix a lot of this by adding in the module specifications; but, that might require you to understand modularity (which is pretty easy, but a barrier nonetheless).
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I want to use Java Visual VM. It's a software which helps you to check your Heap-Memory load. It also provides more functions. But those are not important for me.
The author of my beginner java book says that Java Visual VM is included in Java SE 9. I should be able to find the exe. in the bin folder of my JDK-folder. I tried to use this software and include it in Eclipse, by following the instructions of my book, but it does not work. I can not find the exe of Java Visual VM in my bin folder of my JDK. I have JDK 14 point something.
I hope someone can help me.
From this link : https://visualvm.github.io/download.html
We learn it is no longer included starting java 9
VisualVM has also been distributed in Oracle JDK 6~8 as Java VisualVM.
It has been discontinued in Oracle JDK 9. See the Upgrading Java
VisualVM page to learn how to upgrade to the latest VisualVM.
And this is also a download link, so please help yourself and get the tool ;)
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How can I install 32 bit JDK on Ubuntu 64bit? I need to install it as I am having some problem with eclipse for android development.
The OpenJDK is part of Ubuntu's main repository, so it can be installed with the usual Ubuntu tools. You want package openjdk-7-jdk or openjdk-8-jdk.
Thanks to the "MultiArch" feature Ubuntu inherited from Debian, you can install the 32-bit version of a package on a 64-bit system using the usual tools, such as apt-get or aptitude. Just append :i386 to the package name. For example:
sudo apt-get install openjdk-7-jdk:i386
Any required i368 libraries will then be installed automatically.
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I 'm use to work with Netbeans 7.2.1 on ubuntu 12.04.
Since the update on july 24, it's no more possible to create projects with it. That comes from the update of the openjdk, as mentionned on this topic.
The more convenient solution seems to use oracle-java instead of open-jdk. Hopefully, there are plenty of docs explaining how to switch from one to the other.
Nevertheless, I encounter an issue while trying to install oracle-java7 on my ubuntu.
In a terminal I type in sudo apt-get install oracle-java7-installer
Up to there, everything is going well, but then, the connection to edelivery.oracle.com fails because timeout expires
I'm behind a company proxy, so I assume the problem may come from that. But I'have no clue how to resolve that.
I have Linux Mint, I don't like relying on apt to have Oracle Java, so I did this:
Download the JDK from the Oracle website.
Unpack it in /opt/jdk_17
Create a link from /opt/jdk to /opt/jdk_17 (so every time I update the JDK I just need to update the link)
Add JAVA_HOME=/opt/jdk in /etc/environment
Update (or add) PATH to include /opt/jdk/bin
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How can I manually check if jdk is installed on my machine, and if yes, what version?
If I had jdk in Windows 7, and now I installed Windows 8 separately on the same machine, do I need to reinstall the jdk? Or can I reuse it?
When you install java on windows it can go by default in one of the following locations:
C:\Program Files (x86)\Java
C:\Program Files\Java
If you look in both of these locations, you will see exactly which JDKs and JREs are installed.
If you installed it somewhere else and don't remember, you can still search for java.exe
If by "Can i use it", you mean for use with an IDE like Eclipse or Netbeans, the answer is yes. They can use the JDK files no matter where they are, and whether it has been installed on the OS or not.
java -version will only tell you about a java version that would be on the path, which is not always the case.
If you have two Windows Version and the java installed in a place where both can share it, you can reuse it.
In cmd window type
java
If you see java usage information then you have java installed.
java -version
which display current version of your java.
You may reuse it windows 7 java in windows 8.