I am trying to config my eclipse (Helios) use jdk 7 to compile my code. I didn't install jdk 7 on my Windows XP. But I include all of the jdk contents with my project. It seems the solution provided in this post doesn't work. Compile java code needs JDK. the JRE is enough for running the compiled code. I think we need a way to configure the JDK to be used not just JRE. I tested with a JDK 7 new feature, String in switch, I can compile it in my batch file compile system but cannot use eclipse to compile it.
any idea?
This is what I did to make Eclipse 3.x works with Java 7.
install Java 7 in another machine and then copy the JDK folder into my java application 3rdparty directory (so my machine still use Java 6);
download the Eclipse 3.7.1 from here: eclipse 3.7.1
configure Eclipse by following steps in this post (select 1.7 in Compiler compliance level under the Java Compiler entry);
At least I can use String in Switch now in Eclipse.
Good luck.
Compile java code needs JDK. the JRE is enough for running the
compiled code.
that is right
"But I include all of the jdk contents with my project"
Including those will not change eclipse's compiler behavior. Including files under project build path just makes those classes available for your application development/run-time (or as good as setting CLASSPATH)
Do these :
1 - Install required version of JDK
2 - Choose following menu - Window > Preferences > Java > Compiler - and you will see a drop down to choose the version you want to use.
3 - Read this and this as well.
Good luck for being DBA after 5 yrs. Please consider working on your English as well (no offense please)
Related
I have downloaded the new eclipse 2022-06 and I wanted to know that what version of Java does it run on. What is the JDK and JRE and how can I create a project to run on Java 7 with a compatible JRE? Where do I select those settings or what do I additionally need to download?
Take a look at the official documentation: Eclipse/Installation
You will find for each version of Eclipse the required JRE/JDK to run it.
Instead, if you are looking for how to run a project with a different JRE/JDK, you can take a look at this guide: How to Change Java Version in an Eclipse Project
I'm new to java programming and I haven't used any java IDE,
I intalled Java JDK 8 on my computer and been doing some coding through Notepad++ and compiling it via cmd commands.
Since now that i'm comfortable coding manually, I wanna try to use IDE and decided to get the latest "Eclipse IDE for Java Developers". what I got is actually a .zip file no installation or something which is odd.
My question is does the eclipse uses the JDK I installed on my computer or it has it's own? if so how would I know which version of java does my eclipse run?
and if does use the JDK on my computer, if I want to update the JDK intalled on my computer do I have to uninstall the old one or I can just overwrite it with the new JDK build??
Thanks,
CC
Eclipse uses externally installed JDKs to run itself (it's written in Java, after all) and to provide the core libraries for the code you write (such as the java.* packages). By default, Eclipse will use its own compiler, ECJ, that has deep integrations with the IDE to provide features such as detailed error reporting and sometimes even partial compilation of invalid classes.
It's possible to override the compiler via some plugin (for example, you can explicitly specify a compiler in a POM via m2eclipse, though the default there still uses ECJ), but that's uncommon if you're still compiling Java code.
Eclipse has support for using multiple JDKs, for example for different versions (maybe you have backwards compatibility with 1.6) or different vendors. Depending on how your OS is set up, if your main JAVA_HOME is set through a symlink, you may not need to update Eclipse at all if you perform a minor upgrade. In the case of a major upgrade, though, you will probably need to go to "Installed JREs" and add or modify an entry.
1.the jdk you installed in your computor is global situation. it can effect anywhere if you have configured the environment variables.
2.configured the environment variables,run cmd like this,the java version will be show,enter image description here
3.generally, one JDK , one computor is enough.if you want to update jdk, just download new jdk and override the old jdk .
I started a new project that is just a hello world that has the Commons IO v2.4 Apache Library that uses JDK 1.6 but is unable to run after I build the jar. I added it to the Libraries and Modules just fine, and it executes the methods that I took from the libraries fine on Compile time, but I am using JRE 1.7. I took of the methods to prove that it is just the fact that it is interacting with this library. I did nothing else to this new project.
The JDK for the library is 1.6 but is demanding 1.8 JRE. Is there somethign that I'm missing here? I want to let users run my jar with their minimum JRE being 1.6 so I can target more users, but this is throwign an error.
The actual Error that is being thrown is the major.min error of 52.0, which means that it needs to run it at 1.8 JRE to run a simple hello world.
Try manually selecting language level for your project.
Right click project > Open Module Settings:
On right side under sources tab, change language level to required JDK.
Then click on Project tab on left and make sure both JDK version and language version are at correct version.
I wanted to start learning java but Eclipse is giving me some trouble.
First of all I'm a beginner with Java with little to no knowledge about it. I want to use 'JavaSe-1.7'. I have no clear reason to use it besides using the latest version. After downloading Eclipse (Eclipse IDE for Java Developers) I created a new Java project and selected 'use an execution eviorment JRE : JavaSE-1.7'. This directly popped the notification saying 'The default compiler compliance level for the current workspace is 1.6. The new project will use a project specific compiler compliance level of 1.7.'. I finished creating the project and started following some tutorials.
However I noticed directly I have 2 errors which dont explain anything or have a source. I ignored it and started typing and tried to import 'java.io.console' however it said 'The import java.io cannot be resolved' and I have no idea what is the cause of it neither how to fix this.
Would like some instructions into the right direction.
Thanks in advance
Check your Eclipse preferences: Java -> Installed JREs. The one that you're using should be marked and it should be a JDK not just a JRE.
Also check your project's build path: Right click on the project -> Properties -> Java Build Path
Check in the "libraries" folder whether the JRE System Library is present and if not add it using "Add library"->"JRE System Library" and then select the correct one (from an installed JDK).
You may not have your JDK/JRE set up correctly.
Check the following:
Did you install a JDK or just the JSE? The JDK is needed to compile .java files to .class files. Without it, you can only run java programs, not develop them. If not, download and install it from Oracle website.
Check in Eclipse, if you have the JRE installed there as well. You just need to specify the path to the installation. You can reach this screen via the "Window->Prefrences" menu. see this screenshot:
The message you receive about project specific compiler compliance level is not a problem, it just means that your workspace is set up to comply to java 1.6 but your project will comply to java 1.7 standards. Also, Java 7 in general is no problem whatsoever.
Paths may differ, especially if you're not running a *nix OS. Just point the location to where you installed your JDK.
I decided to give Eclipse (Eclipse 3.7.2 ) a chance because of the plugin "Columns For Eclipse". The IDE I would like to migrate away from ( Visual Slickedit ) has spoiled me with sophisticated column editing features and this plugin has most of them, whereas the default column editing features in Eclipse are too basic for me.
I tried the plugin out at home and I really like it. However, the machine I use at work runs on Java 1.5 and the plugin requires Java 1.6.
I would like to try recompiling the plugin under Java 1.5, as my job uses WebLogic 9.2 which runs on Java 1.5. I don't want to risk compatibility issues by setting up my computer to run on Java 1.6
I have the source code, but it didn't come with directions on how to compile the plugin. It isn't structured in a Maven project.
I'm 100% new to Eclipse so I was wondering if someone could give me step by step instructions for compiling (and installing ) my own copy of the plugin under Java 1.5.
Alternately, is it possible to set up Eclipse 3.7.2 to run on Java 1.6 but always compile in Java 1.5?
Thanks much in advance.
Building and installing the plugin without an existing build script would be quite complicated. For your second option, you can setup the compiler compliance level for the entire IDE:
Or alternatively, you could set it up on a project-by-project bases (Right click project, Properties->Java Compiler).
Yes, it is possible to run Eclipse with Java 6, but use a Java 5 JDK as the default for compilation and runtime. You need to configure Eclipse: Window -> Preferences -> Java -> Installed JREs.
You can also use Java 6 as the development/runtime and set the compiler compliance level to 1.5 (same as 5), but that's a bit dangerous as it doesn't stop you using APIs only available in Java 6; it only enforces language syntax.