Ant is using wrong java version

Question

I'm using Ant 1.7.0 and installed java 1.6 which is in JAVA_HOME.

I want to build a project using java 1.5, so I've exported JAVA_HOME to be my java 1.5 directory.

java -version

says "1.5". When I run Ant it uses java 1.6.

You can write a batch script to specify exactly how to run it. If its just compiling, you could specify the version in the command, like: — James Oravec, Sep 18 '13 at 15:54
Take a look [this answer](https://stackoverflow.com/questions/29743785/i-am-getting-wrong-java-version-on-running-ant-build/61190824#61190824) for wrong JAVA version — Harisudha, Apr 01 '21 at 18:08

score 75 · Answer 1 · answered Apr 15 '11 at 12:47

75

Just had this issue, it happened because I'd first added the build file to the ant-view when the default JRE was 1.6.

There was no project-specific JRE and I changed the default to 1.5, even eclipse was running in 1.5, and JAVA_HOME was 1.5 too. Running the ant target from the command line used JRE 1.5, but within eclipse it still used 1.6.

I had to right-click the ant target, select Run As... and change the JRE under the JRE tab. This setting is remembered for subsequent runs.

answered Apr 15 '11 at 12:47

Lee Kowalkowski

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8

I've just realised the question did not mention Eclipse at all. My answer is for the described problem when using Eclipse. – Lee Kowalkowski Oct 27 '11 at 19:45
3

Thank you for ending a few hours of frustration. – Dark Star1 Jul 26 '13 at 14:13
if you are not using eclipse then check out my answer at the bottom. – Utsav Gupta Sep 13 '14 at 06:02
I love how questions have many flavors of answers for the different environments and setup of our users. – Perdomoff Mar 28 '18 at 18:00

score 34 · Answer 2 · edited Apr 17 '18 at 06:41

34

In Eclipse:

Right click on your build.xml
click "Run As", click on "External Tool Configurations..."
Select tab JRE. Select the JRE you are using.

Re-run the task, it should be fine now.

edited Apr 17 '18 at 06:41

Paolo Forgia

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answered May 24 '13 at 12:37

bram000

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score 25 · Answer 3 · answered Jun 04 '09 at 10:25

25

According to the ant manual, setting JAVA_HOME should work - are you sure the changed setting is visible to ant?

Alternatively, you could use the JAVACMD variable.

answered Jun 04 '09 at 10:25

Michael Borgwardt

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I have ths issue myself atm and JAVA_HOME is pointing to the right JDK, however ant is still reporting the wrong java version. – Dark Star1 Jul 26 '13 at 14:11
JAVACMD as a full path to executable java.exe worked for me (win 10) – kamil.ka Oct 19 '18 at 09:32

score 19 · Answer 4 · answered Jun 04 '09 at 10:28

19

Run ant in verbose mode : ant -v and looks for clues.

answered Jun 04 '09 at 10:28

Robert Munteanu

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This helped me a lot. I first tried building a project into a lib with jdk 1.8. I later discovered I needed to build it on 1.7 instead, so installed jdk 1.7, changed JAVA_HOME but still ant kept building it with 1.8. Using `ant -v` I discovered that ant was correctly using jdk1.7, yet the build was omitting all classes on the temporary folder because they were already there because of my previous attempt. So all I did was delete the temporary folder, and it recreated them, this time with jdk 1.7 like I wanted. Might help someone – Mauro Banze Jun 02 '16 at 11:44

simon_d · Answer 5 · 2015-04-17T01:41:13.477

You can use the target and source properties on the javac tag to set a target runtime. The example below will compile any source code to target version 1.4 on any compiler that supports version 1.4 or later.

<javac compiler="classic" taskname="javac" includeAntRuntime="no" fork=" deprecation="true" target="1.4" source="1.4" srcdir="${src}" destdir="${classes}">

Note: The 'srcdir' and 'destdir' are property values set else where in the build script, e.g. <property name="classes" value="c:/classes" />

score 11 · Answer 6 · edited Sep 06 '15 at 18:00

11

You could achieve that with following steps, if you are using Eclipse IDE:

Right click on the task in your ant build file (build.xml).
Mouse over "Run As", click on "External Tool Configurations...".

Add followings to "Arguments":

-Dant.build.javac.target=1.5 -Dant.build.javac.source=1.5

edited Sep 06 '15 at 18:00

Greg Dubicki

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answered Sep 23 '10 at 22:21

Sheng Chien

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score 7 · Answer 7 · answered Feb 25 '16 at 17:16

7

Build file:

<target name="print-version"> 
   <echo>Java/JVM version: ${ant.java.version}</echo> 
   <echo>Java/JVM detail version: ${java.version}</echo> 
</target>

Output:

[echo] Java/JVM version: 1.5
[echo] Java/JVM detail version: 1.5.0_08

answered Feb 25 '16 at 17:16

Adriano

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score 6 · Answer 8 · edited Jan 23 '11 at 01:08

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You can also specify in a javac task what level of compatibility ( 1.4, 1.5, 1.6 ) you want to use, you can set the "source" and "target" level values, check the docs here : Javac task documentation

edited Jan 23 '11 at 01:08

martin clayton

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answered Jun 04 '09 at 10:44

Billy

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To guarantee compatibility, also add the `-bootclasspath` option when compiling. – Andrew Thompson Jun 22 '11 at 10:40

score 5 · Answer 9 · answered Jul 18 '11 at 16:27

This is rather an old question, but I will add my notes for future references.

I had a similar issue and fixed it by changing the order of the exports in the PATH variable.

For example I was using a method of concatenating strings to my PATH by doing (this is just an example):

$> export PATH='$PATH:'$JAVA_HOME

If my variable PATH already had a java in it, the last value would be meaningless, thus the order would matter. To solve this I started inverting it by adding my variable first, then adding the PATH.

Following this idea I inverted the order that ANT_HOME was being exported. Adding JAVA_HOME before ANT_HOME.

This could be just a coincidence, but it worked for me.

This happened to me too. I wasn't sure what entry was conflicting with JAVA_HOME but when I put it at the beginning of the PATH, it worked. — Inversus, Sep 24 '12 at 22:28

Abdollah · Answer 10 · 2021-02-12T05:30:24.077

JAVACMD is an Ant specific environment variable. Ant doc says:

JAVACMD—full path of the Java executable. Use this to invoke a different JVM than JAVA_HOME/bin/java(.exe).

So, if your java.exe full path is: C:\Program Files\Java\jdk1.8.0_211\bin\java.exe, create a new environment variable called JAVACMD and set its value to the mentioned path (including \java.exe). Note that you need to close and reopen your terminal (cmd, Powershell, etc) so the new environment variable takes effect.

score 2 · Answer 11 · answered Sep 13 '14 at 06:01

2

If you are not using eclipse. Then you can change the ant java property directly on the file as mentioned here.

http://pissedoff-techie.blogspot.in/2014/09/ant-picks-up-incorrect-java-version.html

answered Sep 13 '14 at 06:01

Utsav Gupta

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score 2 · Answer 12 · edited Jan 13 '16 at 19:20

2

Use the following 2 properties for javac tag:

fork="yes"  
executable="full-path-to-the-javac-you-want-to-use".

Explaination of the properties can be found here

edited Jan 13 '16 at 19:20

MWiesner

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answered Jan 13 '16 at 19:17

ArKumar

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score 1 · Answer 13 · edited May 08 '18 at 06:43

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Set your JAVA_HOME environment variable with the required java version (in your case java 1.5), then in build.xml use executable="${JAVA_HOME}/bin/javac" inside <javac></javac> tag .

example:

<target name="java compiler" description="Compiles the java code">
    <javac executable="${JAVA_HOME}/bin/javac" srcdir="./src" 
        destdir="${build.dir}/classes"> 
    </javac> 
</target>

edited May 08 '18 at 06:43

coder

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answered May 08 '18 at 05:31

Vikas Naik

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score 1 · Answer 14 · answered Jun 22 '11 at 10:03

1

If you run Ant from eclipse, the eclipse will use jdk or jre that is configured in the class-path(build path).

answered Jun 22 '11 at 10:03

zawhtut

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Yes by default, but it can be configured for every ant file differently, so to check every one can be crucial... – Nick Russler Dec 11 '12 at 15:32
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To find out for sure what java version ant is using:`` – dmolony Apr 04 '13 at 10:50
Learning about ${ant.java.version} was a great thing for me, thanks! – javydreamercsw Apr 19 '13 at 17:33
where would i put this in the build.xml ? – jesses.co.tt Apr 04 '16 at 16:23

score 0 · Answer 15 · edited May 11 '17 at 00:22

0

According to the Ant Documentation, set JAVACMD environment variable to complete path to java.exe of the JRE version that you want to run Ant under.

edited May 11 '17 at 00:22

Unheilig

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answered May 11 '17 at 00:04

Harry

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score 0 · Answer 16 · answered Dec 01 '17 at 12:35

By default the Ant will considered the JRE as the workspace JRE version. You need to change according to your required version by following the below.

In Eclipse:

Right click on your build.xml click "Run As", click on "External Tool Configurations..." Select tab JRE.
Select the JRE you are using.
Re-run the task, it should be fine now.

isapir · Answer 17 · 2021-04-14T19:08:52.633

If your build file does not already have it (some do, e.g. Apache Tomcat), you can add an echoproperties target to build.xml, e.g.

<target name="echoproperties">
    <echoproperties/>
</target>

Then you can run the ant task echoproperties and look for "java.version" or ant -v and look for "Java version", e.g. on my machine

ant echoproperties | grep java.version

shows

[echoproperties] java.version=11.0.9.1

and

ant -v | grep -i "java version"

shows

Detected Java version: 11 in: /opt/java/zulu11.43.55-ca-jdk11.0.9.1-linux_x64

Ant is using wrong java version

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