I need to use some java library in MATLAB. I did use it in MATLAB (Unix version), but now I have to do it on MATLAB (Win64), as well. As far as I know, this is a project developed in unix. I did simply compile it using
ant
command in Ubuntu.
Since I'm a beginner to java compiling, I thought of installing ant on Windows and running
c:\java\ant\bin\ant
command in the path. However when I do this, it says that:
build.xml:22: Javadoc failed: java.io.IOException:
Cannot run program "javadoc.exe": CreateProcess error=2
Here is the build.xml file:
<project default="all">
<target name="all" depends="doc,jar" />
<target name="compile">
<mkdir dir="build/classes" />
<mkdir dir="build/examples" />
<javac includeantruntime="false" debug="on" srcdir="src/main/java"
destdir="build/classes" target="1.5" />
<javac includeantruntime="false" srcdir="src/main/example/"
classpath="build/classes" destdir="build/examples" />
</target>
<target name="jar" depends="compile">
<jar destfile="dist/java_websocket.jar">
<fileset dir="build/classes" includes="**/*.class" />
</jar>
</target>
<target name="doc">
<delete dir="doc" />
<javadoc sourcepath="src/main/java" destdir="doc" />
</target>
<target name="clean">
<delete dir="build" />
</target>
</project>
When I try to search about this issue, I've come up with so many answers that are about Java Eclipse compilations, which I'm a total stranger to.
If you use maven to compile these projects, thats fine. I just need some guidance.
Here is the github link of the java project that I'm trying to compile (on Win64), if you would like to see any further information: https://github.com/TooTallNate/Java-WebSocket
And here is the build instructions (I'm guessing for Unix): https://github.com/TooTallNate/Java-WebSocket/blob/master/README.markdown
Note that I sadly use Windows 8 (x64) and I currently have jdk1.7.0_21 installed on the path "C:\Program Files\Java\jdk1.7.0_21" which is also the system variable JAVA_HOME. ANT_HOME variable is "c:\java\ant"
Please take a moment from your precious time and help me to find a solution, if you have any knowledge about this issue. Any help will be greatly appreciated.
Best regards.
If it compiles on ubuntu with just ant, there is no need for either maven or eclipse. The problem is likely that the PATH variable does not include the jdk. Look into c:\Programs\Java and find the javadoc.exe. Its directory must go into PATH. To set the dir in PATH, go to (roughly, have no windows around) computer / properties / advanced / environment variables / system and find the PATH variable. Append the directory you found by using semicolon as the separator.
Related
I have a project I build using ant and eclipse which I'd like to have be compatible with Java 8.
When I try running the jar using Java 8, I get the following error:
$ /usr/lib/jvm/java-8-openjdk-amd64/bin/java -jar hypnos.jar
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError:
org/joshuad/musicplayer/MusicPlayerUI has been compiled by a more recent version of
the Java Runtime (class file version 53.0), this version of the Java Runtime only
recognizes class file versions up to 52.0
So it appears that it's compiling using Oracle's Java 9 (which is installed on my system) but I can't find the place in eclipse where this is designated. Everything I see seems to suggest that we're using java 8 (screenshots below).
I feel like I must be missing something, but I can't figure out where. What do I have to do to get this jar to be compatible with Java 8 / class file version 52.0?
Project > Properties > Java Build Path
Project > Properties > Java Compiler
Window > Preferences > Compiler
Right Click Ant Build File > Run As > External Tools Configuration
Ant Build File
<project name="Hypnos Music Player" default="compile" basedir=".">
<property name="src" location="src"/>
<property name="build" location="build"/>
<property name="jarFile" location="hypnos.jar"/>
<path id="class.path">
<fileset dir="lib">
<include name="**/*.jar" />
</fileset>
<pathelement location="${jarFile}" />
</path>
<target name="init">
<tstamp/>
<mkdir dir="${build}"/>
</target>
<target name="compile" depends="init" description="compile the source">
<javac fork="yes" includeantruntime="false" srcdir="${src}" destdir="${build}">
<classpath refid="class.path" />
</javac>
</target>
<target name="jar" depends="compile" description="Create a jar.">
<jar destfile="${jarFile}" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="org.joshuad.musicplayer.MusicPlayerUI" />
<attribute name="Class-Path" value="lib/commons-cli-1.4.jar lib/jaad-0.8.4-nospi.jar
lib/jaudiotagger-2.2.6-SNAPSHOT.jar lib/jflac-1.2.jar
lib/jl1.0.1.jar lib/jogg-0.0.7.jar lib/jorbis-0.0.15.jar
lib/vorbisspi1.0.3.jar" />
</manifest>
</jar>
</target>
</project>
What is your $JAVA_HOME environment variable?
I recently had a similar problem and it turns out that Ant seems to ignore many settings provided by Eclipse and only uses $JAVA_HOME. I discovered this by placing the following in build.xml:
<target name="jdk_version_validation">
<echo message="Java Version: ${java.version}" />
<echo message="Java home: ${java.home}" />
<echo message="JAVA_HOME: ${env.JAVA_HOME}" />
<echo message="JAVACMD: ${env.JAVACMD}" />
</target>
Which got me this:
jdk_version_validation:
[echo] Java Version: 1.7.0_80
[echo] Java home: C:\Program Files\Java\jre7
[echo] JAVA_HOME: C:\Program Files\Java\jdk1.8.0_131\
[echo] JAVACMD: C:\Program Files\Java\jdk1.7.0_80\bin
I found that the only sure way to predict which version Ant will produce is by brute-forcing the following in build.xml:
<property name="ant.build.javac.source" value="1.7"/>
<property name="ant.build.javac.target" value="1.7"/>
So, my recommendation to you: Try placing in your build.xml the following:
<property name="ant.build.javac.source" value="1.8"/>
<property name="ant.build.javac.target" value="1.8"/>
Update, for the benefit of those with a variation of the problem described in the OP, to eliminate any possibility of "Eclipse fooling Ant":
Go to Window > Preferences > Java > Installed JREs and try leaving only the target JRE, making sure it is the one inside the JDK folder (not the sibling one directly under the Java folder).
Go to Project > Properties > Java Compiler and check Enable project specific settings, making sure that the Compiler compliance level is set to the target JRE java version.
In addition to what datv said above, I'll add from experience:
Ant's javac, java, and junit tasks have a jvm attribute that determines how to run the JDK/JRE, if fork="true". Unfortunately, it only sets the raw launcher, and doesn't change all the other settings. When I set the jvm attribute to the full path of a Java 8 JRE, turning on ant's -d switch shows that it is being used as the executable, but followed by
'-Djava.specification.version=9'
'-Dsun.boot.library.path=C:\Java\x64\jdk-9.0.1\bin'
'-Djava.home=C:\Java\x64\jdk-9.0.1'
'-Djava.runtime.version=9.0.1+11'
'-Djava.version=9.0.1'
'-Djava.library.path=...;C:\Java\x64\jdk-9.0.1\bin;.....
'-Djava.vm.version=9.0.1+11'
'-Djava.class.version=53.0'
all of which take precedence.
It turns out that Ant cares more about the JAVACMD environment variable when it starts up. In the situation above, our build framework had set JAVACMD to C:\Java\x64\jdk-9.0.1\bin\java, and the individual jvm= and executable= attributes on specific tasks were... not "ignored" really, merely pointless and misleading.
I have been struggling with this for two days now. I created a very simple HelloWorld class to test if I can get this working but I was not able to.
I get Error- Could not find or load main class...
It works from Eclipse or run task from the script. But double-clicking .jar or running it from CMD gives me the error. What are some possible reasons for this error? Class-path? environmental variables? directory structure? Please help!
package com.hellojava;
public class HelloWorld {
public static void main(String[] args)
{
System.out.println("Hello World!");
}
}
My build.xml
<project name="TestProject" basedir="." default="main">
<property name="src.dir" value="src"/>
<property name="build.dir" value="build"/>
<property name="classes.dir" value="${build.dir}/classes"/>
<property name="jar.dir" value="${build.dir}/jar"/>
<property name="main-class" value="com.hellojava.HelloWorld"/>
<target name="clean">
<delete dir="${build.dir}"/>
</target>
<target name="compile">
<mkdir dir="${classes.dir}"/>
<javac srcdir="${src.dir}" destdir="${classes.dir}"/>
</target>
<target name="jar" depends="compile">
<mkdir dir="${jar.dir}"/>
<jar destfile="${jar.dir}/${ant.project.name}.jar" basedir="${classes.dir}">
<manifest>
<attribute name="Main-Class" value="${main-class}"/>
</manifest>
</jar>
</target>
<target name="run" depends="jar">
<java jar="${jar.dir}/${ant.project.name}.jar" fork="true"/>
</target>
<target name="clean-build" depends="clean,jar"/>
<target name="main" depends="clean,run"/>
run:
[java] Hello World!
main:
BUILD SUCCESSFUL
Total time: 5 seconds
Manifest-Version: 1.0
Ant-Version: Apache Ant 1.9.2
Created-By: 1.7.0_11-b21 (Oracle Corporation)
Main-Class: com.hellojava.HelloWorld
**Edited:
java -jar TestProject.jar works but javaw -jar TestProject.jar does not. However, I solved the problem- see answer I posted.
The usual syntax to run a jar file is java -jar TestPractice.jar.
If this fails, some analysis is required.
Open your jar file with WinZip, and extract to a temporary directory.
Check that HelloWorld.class file is present, and in the correct directory.
Check that there is a META-INF/MANIFEST.MF file, and it contains a line reading
Main-Class: com.hellojava.HelloWorld I don't see anything in your Ant script that would generate this file.
If all that is OK, your program will run.
For more information, take a look at how to create a bundled runnable jar using Ant
Problems Solved!
I had to change the registry to a correct Java version that I am using. It was set to the previous version of Java that was in my comp.
I can run .jar files through cmd, but I cannot double click them
Also, I noticed that javaw -jar file.jar does not work for me while java -jar file.jar works.
I changed the program that opens .jar files by "open with" and select java instead of javaw. This now solves the problem- I do have one more problem though. I wonder why javaw does not work but for now I'm happy this is working :)
I had the same problem. Application worked fine on my PC but on some PCs I get the same error. Try to upadte Java runtime on machines where your app donesn't work. For example I worked with JRE7 and on PC where app was not working there was Java 1.6 installed.
I usually code with IDEs like Intellij Idea or Eclipse, but due to several reasons, I no longer have access to an IDE, and I'd like to be able to code in Java on a remote Linux machine through a ssh terminal.
Making simple progams with only a few classes is easy, but some of my projects have several libraries and several separate .java files. I also need to export to a .jar file.
For example, I have the following file organisation:
project/
src/
a.java
b.java
c.java
libs/
lib1.jar
lib2.jar
out/
export_here.jar
someconfig.conf
The java app consists of the a, b, and c .java files, uses libraries lib1 and lib2, and the file someconfig.conf needs to be inside the export jar.
I want to know how to easily compile and build a project such as this.
In other words, I just want to know how to export my project into a runnable jar the right way.
I expect this can be done with a few commands. If so, I plan to make a shell script to automate everything.
Thanks in advance!
As suggested by other users you need to use a build management tool to do this like Ant, Maven etc. I have used Ant quiet frequently to do these kind of automated tasks. In order to install and Use Ant you can refer How To Install Apache Ant
After that the main task is to write your automation script and that is called a build xml in ant world. Here is a sample build.xml file you can refer to start with:
<project>
<target name="clean">
<delete dir="build"/>
</target>
<target name="compile">
<mkdir dir="build/classes"/>
<javac srcdir="src" destdir="build/classes"/>
</target>
<target name="jar">
<mkdir dir="build/jar"/>
<jar destfile="build/jar/HelloWorld.jar" basedir="build/classes">
<manifest>
<attribute name="Main-Class" value="oata.HelloWorld"/>
</manifest>
</jar>
</target>
<target name="run">
<java jar="build/jar/HelloWorld.jar" fork="true"/>
</target>
</project>
And for more information on the above sample You can visit this
In General you can read more at How to create build.xml
After creating your build.xml you can run ant by ant <path to build.xml> or ant in case your build.xml lies in current directory
Hope this helps you in right direction
I'm trying to figure out how to get Travis CI working with my little Java library on Github.
The problem seems to be that whenever the build process gets to the compilation stage, it won't compile the unit tests because it can't seem to find the JUnit jar file. Of course the Ant script works beautifully on my own computer, but I can't get the classpath right on Travis. How am I supposed to know where (or even if) they installed JUnit?
Here's my Ant script:
<project>
<target name="test">
<delete dir="build" />
<mkdir dir="build" />
<javac includeantruntime="false" srcdir="src" destdir="build" />
<javac includeantruntime="false" srcdir="tests" destdir="build" classpath="/usr/share/java/junit.jar" />
<junit printsummary="on">
<classpath>
<pathelement location="build" />
<pathelement path="/usr/share/java" />
</classpath>
<test name="FactorizeTest" />
</junit>
</target>
</project>
Here's the project link, notice the pretty "build failing" icon. Yay.
https://github.com/The-Craw/PrimeFactorizer
And finally here's the link to the build output. You can also get this from clicking the build icon.
https://travis-ci.org/The-Craw/PrimeFactorizer
You need the junit.jar on your classpath. (I think that is in Ant's lib directory on your locale machine).
You may have a look at the project template https://github.com/mplacona/java-junit-template-project
I am having a little trouble with my first ever ant build in eclipse, here is my build.xml build file.
<project name="Rutherford" default="dist" basedir=".">
<description>
simple example build file
</description>
<!-- set global properties for this build -->
<property name="src" location="src"/>
<property name="build" location="build"/>
<property name="dist" location="dist"/>
<property name="libs" value="libs"/>
<path id="classpath">
<fileset dir="${libs}" includes="**/*.jar"/>
</path>
<target name="init">
<!-- Create the time stamp -->
<tstamp/>
<!-- Create the build directory structure used by compile -->
<mkdir dir="${build}"/>
</target>
<target name="compile" depends="init"
description="compile the source " >
<!-- Compile the java code from ${src} into ${build} -->
<javac srcdir="${src}" destdir="${build}" classpathref="classpath">
<compilerarg line="-encoding utf-8"/>
</javac>
</target>
<target name="dist" depends="compile"
description="generate the distribution" >
<!-- Create the distribution directory -->
<mkdir dir="${dist}/lib"/>
<!-- Put everything in ${build} into the MyProject-${DSTAMP}.jar file -->
<jar jarfile="${dist}/MyProject-${DSTAMP}.jar" basedir="${build}">
<manifest>
<attribute name="Main-Class" value="nat.rutherford.DesktopStarter"/>
</manifest>
</jar>
</target>
<target name="run">
<java jar="${dist}/MyProject-${DSTAMP}.jar" fork="true"/>
</target>
<target name="clean"
description="clean up" >
<!-- Delete the ${build} and ${dist} directory trees -->
<delete dir="${build}"/>
<delete dir="${dist}"/>
</target>
</project>
It compiles ok with no warnings or errors, but when I try to run the .jar it says 'Could not find the main class: nat.rutherford.DesktopStarter. Program will now exit' =(
I have read a ton of pages on the matter but so far nothing conclusive.
I was able to compile it using Eclipse -> File -> Export ->Java -> Runnable Jar File. But I use some UTF-8 encoded .txt files that it seems not to be able to deal with that way and I need them! ie I have greek characters that should read...dσ/dΩ... but currently read... dÃ/d©... which isn't going to work ^^
So basically I need to make my Ant build work, baring in mind that it needs to be able to handle my UTF-8 encoded .txt files too.
The problem is in your task dist when you create your jar. If your compilation is right and there is no problem when you package your jar. Things that are wrong:
<mkdir dir="${dist}/lib"/> -> this don't have mean, you don't use it never
second you are not including your libraries in your jar, then when you try to execute your jar it doesn't work that why you are seeing the error message Could not find the main class: nat.rutherford.DesktopStarter. Program will now exit You could see that your libraries aren't within your jar using Winzip or similar. I suppose that you are seeing your problem when you try to execute the jar directly using windows or similar. A good way to see what is happening, seeing the problem printed in the console is executing your jar in the next way: java -jar MyProject-20120102.jar
See: How to include your libraries in you jar?
And if you want to know more about jar packaging using ant try this.
Another thing that you need to modify the Class-path attribute in your manifest to include the libraries within your ${libs} folder.
It looks like you've added a manifest to your executable JAR that spells out nat.rutherford.DesktopStarter as your main class.
I'd recommend that you open the JAR and verify that the manifest.mf appears and does indeed say what your Ant build.xml does.
I'd also verify that your DesktopStarted.class appears in a folder path nat.rutherford. If it doesn't, the JVM won't find it.