I'm running snow leopard and I just wrote a Java class on eclipse. The eclipse project references a user library which itself points to a bunch of jar files I've got somewhere in the system. When I run the app through eclipse, everything goes smoothly.
Then I export the class as a jar file and try to run it form the terminal by typing:
java - jar myApp.jar
It throws a java.lang.NoClassDefFoundError exception, meaning that it can't find the libraries I try to reference.
Knowing that my user library jar files are in /Users/myname/tempJars, I also tried to either mention the classpath using the -cp option
(java -cp /Users/myname/tempJars -jar myApp.jar) or to directly reference it in the manifest file. Both attempts failed and the error is the same.
These libraries are Java 1.5 libraries, so I thought I should try and reference another java version by mean of the JAVA_HOME environment variable. I built the following script:
export JAVA_HOME=/System/Library/Frameworks/JavaVM.framework/Versions/1.5/Home
export PATH=$JAVA_HOME/bin:$PATH
export CLASSPATH=$CLASSPATH:/Users/myname/tempJars
java -jar myApp.jar
Again, no good. I googled how to execute jars in snow leopard, found the 32/64 bit big deal in some places and even tried executing with the -d32 option, but still to no avail.
Since the same code executes just fine in eclipse, I'm pretty convinced it's just a matter of setting up the JVM so that it includes the user libraries correctly.
Could anyone help me with this?
Thanks in advance.
You need to list the JARs themselves out on the classpath, not just the directory containing them. (Listing the directory is for when you have unarchived .class files in the package hierarchy lying around)
You will probably need to do -cp /Users/myname/tempJars/libA.jar:/.../libB.jar
I believe some (but potentially not all) JVMs support wildcards so -cp /Users/myname/tempJars/* or some variant thereof may work.
Related
IDEA has a great built-in feature - decompiler. It works great.I can copy source code, but I cannot find option to extract all decompiled java classes to java files.
This project has a lot of java classes and packages, so I will be to long to copy this manually.
Does anyone know how to extract to java source files.
Thx
As of August 2017 and IntelliJ V2017.2, the accepted answer does not seem to be entirely accurate anymore: there is no fernflower.jar to use.
The jar file is called java-decompiler.jar and does not include a main manifest... Instead you can use the following command (from a Mac install):
java -cp "/Applications/IntelliJ IDEA.app/Contents/plugins/java-decompiler/lib/java-decompiler.jar" org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler
(you will get the wrong Usage command, but it does work).
Follow instructions for IntelliJ JD plugin. Or see an excerpt from the instructions below.
java -jar fernflower.jar [<source>]+ <destination>
+ means 1 or more times
<source>: file or directory with files to be decompiled. Directories are recursively scanned. Allowed file extensions are class, zip and jar.
<destination>: destination directory
Example:
java -jar fernflower.jar -hdc=0 -dgs=1 -rsy=1 -lit=1 c:\Temp\binary\ -e=c:\Java\rt.jar c:\Temp\source\
Be aware that if you pass it a ".jar" file for the source, it will create another ".jar" file in the destination, however, within the new ".jar" file, the files will be .java instead of .class files (it doesn't explode the jar).
UPDATE
People ask me: How do I get the fernflower.jar?
If you have any IntelliJ product installed, chances are that you already have the Fernflower decompiler on your computer. IntelliJ IDEA comes with Java Bytecode Decompiler plugin (bundled) which is a modern extension of Fernflower.
Locate the file in ${IntelliJ_INSTALL_DIR}\plugins\java-decompiler\lib\java-decompiler.jar (example: C:\Program Files\JetBrains\IntelliJ IDEA 2018\plugins\java-decompiler\lib).
Copy it somewhere and rename to fernflower.jar (optional).
This JAR is not executable, so we can't run it using java -jar. However something like this works:
java -cp fernflower.jar org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler [<source>]+ <destination>
org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler is the class that contains the main method to run the decompiler.
Example:
mkdir output_src
java -cp fernflower.jar org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler -hdc=0 -dgs=1 -rsy=1 -lit=1 ./input.jar ./output_src
If you don't have IntelliJ products installed, either download it now (available on jetbrains.com) or make your own decompiler executable from sources (available on Github).
Open an existing project or create a new one.
Go to Project structure settings > Libraries. Add the jar you want to decompile in libraries by clicking the + symbol.
Go to the Project tool window shown on the left. Search for jar name that you added in the previous step. Navigate to the desired class or package.
You can see the decompiled java files for that jar.
You could use one of these (you can both use them online or download them, there is some info about each of them) :
http://www.javadecompilers.com/
The one IntelliJ IDEA uses is fernflower, but it can't handle recent things - like String/Enum switches, generics (didn't test this one personally, only read about it), ...
I just tried cfr from the above website and the result was the same as with the built-in decompiler (except for the Enum switch I had in my class).
Try
https://github.com/fesh0r/fernflower
Download jar from
http://files.minecraftforge.net/maven/net/minecraftforge/fernflower/
Command :
java -jar fernflower.jar -hes=0 -hdc=0 C:\binary C:\source
Place your jar file in folder C:\binary and source will be extracted and packed in a jar inside C:\source.
Enjoy!
The decompiler of IntelliJ IDEA was not built with this kind of usage in mind. It is only meant to help programmers peek at the bytecode of the java classes that they are developing. For decompiling lots of class files of which you do not have source code, you will need some other java decompiler, which is specialized for this job, and most likely runs standalone, like jad, fernflower, etc.
Some time ago I used JAD (JAva Decompiler) to achieve this - I do not think IntelliJ's decompiler was incorporated with exporting in mind. It is more of a tool to help look through classes where sources are not available.
JAD is still available for download, but I do not think anyone maintains it anymore: http://varaneckas.com/jad/
There were numerous plugins for it, namely Jadclipse (you guessed it, a way to use JAD in Eclipse - see decompiled classes where code is not available :)).
I use JD-GUI for extract all decompiled java classes to java files.
Someone had gave good answers. I made another instruction clue step by step.
First, open your studio and search. You can find the decompier is Fernflower.
Second, we can find it in the plugins directory.
/Applications/Android Studio.app/Contents/plugins/java-decompiler/lib/java-decompiler.jar
Third, run it, you will get the usage
java -cp "/Applications/Android Studio.app/Contents/plugins/java-decompiler/lib/java-decompiler.jar" org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler
Usage: java -jar fernflower.jar [-<option>=<value>]* [<source>]+ <destination>
Example: java -jar fernflower.jar -dgs=true c:\my\source\ c:\my.jar d:\decompiled\
Finally, The studio's nest options for decompiler list as follows according IdeaDecompiler.kt
-hdc=0 -dgs=1 -rsy=1 -rbr=1 -lit=1 -nls=1 -mpm=60 -lac=1
IFernflowerPreferences.HIDE_DEFAULT_CONSTRUCTOR to "0",
IFernflowerPreferences.DECOMPILE_GENERIC_SIGNATURES to "1",
IFernflowerPreferences.REMOVE_SYNTHETIC to "1",
IFernflowerPreferences.REMOVE_BRIDGE to "1",
IFernflowerPreferences.LITERALS_AS_IS to "1",
IFernflowerPreferences.NEW_LINE_SEPARATOR to "1",
**IFernflowerPreferences.BANNER to BANNER,**
IFernflowerPreferences.MAX_PROCESSING_METHOD to 60,
**IFernflowerPreferences.INDENT_STRING to indent,**
**IFernflowerPreferences.IGNORE_INVALID_BYTECODE to "1",**
IFernflowerPreferences.VERIFY_ANONYMOUS_CLASSES to "1",
**IFernflowerPreferences.UNIT_TEST_MODE to if (ApplicationManager.getApplication().isUnitTestMode) "1" else "0")**
I cant find the sutialbe option for the asterisk items.
Hope these steps will make the question clear.
2022 UPDATE
Like any experienced developer who's being honest, I have to admit it -- I'm lazy. More is less and less is better when it comes to typing. The answers from #naXa and #yan are fine, except for having to open a terminal and type :-(
To decompile a jar right from within intellij, create a reusable JAR Application run configuration:
Copy java-decompiler.jar to a folder in your project (I used lib). Get from:: Windows: C:\Program Files\Intellij\plugins\java-decompiler\lib; or from github (documentation is here)
Copy source jar or class files to same folder
Create a run configuration with settings like these:
Path to JAR: browse to java-decompiler.jar
Program arguments: -hdc=0 -dgs=1 -rsy=1 -lit=1 your.jar lib
Working directory: lib
JRE: 11
In this case, your.jar is the source and lib is the output directory. Save it, run it, and watch it do its thing :-)
Need to do it again with different class files or jars? Duplicate the run config and update Program arguments.
---- package jar (java) jar -cvfM0 test.jar
---Decompile jar(class)>>>>>>>>>jar(java) java -cp "C:\Program Files\JetBrains\IntelliJ IDEA 2020.1\plugins\java-decompiler\lib\java-decompiler.jar" org.jetbrains.java.decompiler.main.decompiler.ConsoleDecompiler -dgs=true C:\ Users\luo\Desktop\sf1\pxks\test.jar C:\Users\luo\Desktop\sf1
Unzip manually
Or use the following command to decompress
find the path
cd..
decompress
jar -xvf test.jar
Reference http://t.csdn.cn/3YLK4
I'm currently a student at a high school, and I found a game programming competition for a club called FBLA. I had a few questions about the competition, and so I emailed them.
I made a post earlier on Computer Science Stack Exchange, where you can view here.
Now after receiving feedback from the question, someone commented that I should post my next question on this website.
My question is that how would I be able to package a Java JAR file with the native libraries, and then create an EXE out of it, so it will be a stand alone?
In my theory, I would have to create the jar, and put the required native files when a person installs java on their machine, into that JAR file, and then I can use a program such as FatJar or JSmooth.
If I'm wrong, or how I could understand a bit more on how jars are ran, it would help considerably.
Update Nov. 8, 2014
I finally got back around to messing with it, and I downloaded Launch4j. I set up and did everything with it, and I make an executable, which contains all of java's core native files. I uninstalled all of my programs dealing with java, and when I went to run it, it still required java.
Once again to state what I need to happen:
What needs to happen is the executable will be able to run even if there's not any version of Java installed on the judge's computer.
I would reccomend you use launch4j. http://launch4j.sourceforge.net
I've used it for some larger projects and it worked very well.
It can encapsulate your jar, dependencies and even a JRE into a windows in executable. It has a GUI or you can run from the command line.
Checkout Packr, created by libGDX team: https://github.com/libgdx/packr
To make your jar executable, you specify the main class of your application, any extra jar files it may require and so on in the jar's manifest file:
Main-Class: MyAppMain
Class-Path: MyLib.jar
Then you use the jar utility from the Java SDK to package your classes and resource files, specifying the m option and the name of your manifest file:
jar cvfm MyApp.jar MyApp.mf *.class *.gif
This will result in the creation of MyApp.jar. Now, if you type
java -jar MyApp.jar
the Java launcher will read the manifest from MyApp.jar, place that file and MyLib.jar on classpath and invoke the main method from the class MyAppMain.
Now, if your Java app needs native libraries, you also need to specify the java.library.path property pointing to the directory(ies) holding those:
java -Djava.library.path=.\bin -jar MyApp.jar
For more info and alternative solutions, refer to my article.
I have been researching this for weeks and can't seem to get it figured out.
I have a Java program that I have written using NetBeans. It has several imports or .jar files it relies on. It runs fine in NetBeans. But I can't figure out how to call the .jar files and compile from the bash command line. I am using a Mac. I have read several posts on this and none so far have made sense to me. There are 26 imports being used in the program. I don't know if I need to use Ant or specify -CP or Classpath to compile. Surely I don't have to type each one of the .jar files out to compile this from the bash command line?
Java(TM) SE Runtime Environment (build 1.7.0_09-b05)
You should be able to simply use ant with the build.xml in the Netbeans project directory. It should "just work" for you. The project will likely not build WITHOUT Netbeans installed (if you tried moving the project to a different machine, for example), but with Netbeans, it should work out of the box.
If you don't have Ant installed, you'll need to install it.
Addenda:
To build it, if you have Ant installed, you should be able to simply go the project directory, where the build.xml file is, and type "ant", and it should build and put stuff in the dist directory.
If you go in to the dist directory and type java -jar yourapp.jar, it should run, because the manifest in the jar will point to the nearby lib jar files. If you want to distribute the app, there are different options for java, such as making a Mac compatible application, or a Windows EXE, you'll need to search for those. Or you can simply distribute the contents of the dist directory and write a script to do that whole java -jar yourapp.jar command.
If you are using Java 1.6 or above, you can toss all 26 jar files into a folder and simply add
-cp folder_name/*
as your classpath argument.
Some other options are 1.) type all 26 jar files on the command line (using the -cp argument as you have mentioned) 2.) use Ant or Maven or some other build tool and list those 26 jar files in the config file for said build tool or 3.) write a quick-and-dirty shell script that will set the CLASSPATH environment variable for you and then run your javac command.
first off let me start by saying I am completely new to Java, but to give you an idea of how new; I started reading lots of books, examples and so forth and began programming Java using Eclipse about 2 months ago. However, I found a really cool bit of advise about using notepad and the terminal to program instead. Kinda crazy for a newbie to go the hard route, but I love a challenge and I'm serious about learning.
So, In Eclipse I had a really good grasp of how to import, add jars compile etc. When I started using pico and using the terminal (I'm running ubuntu) to compile all went really well, until I wanted to use packages. I've spent two days pulling my hair out because no matter what I do I can't figure it out.
I'm trying to use the acm.jar (which I have many times in Eclipse) however I'm completely lost on how to use it when compiling from the javac in terminal.
So what I'm asking for, is for someone to explain the process getting my jar file to work.
All I'm using to create my java programs is the pico (or notepad) and the javac in the terminal.
To compile and run a java class using external libraries, you have to add that library to the classpath. The classpath is the set of places where the java compiler and the JVM look to find any external libraries/classes that it needs during the process of compiling/executing.
Setting the classpath can be done in 2 ways:
Set an environment variable called CLASSPATH
Set it when your run javac/java
Setting the classpath when running javac/java is done like this:
javac -cp path/to/jar1:path/to/jar2:path/to/jar3:path/to/dirContainingClasses
yourMainClass.java
To run:
java -cp path/to/jar1:path/to/jar2:path/to/jar3:path/to/dirContainingClasses
yourMainClass
: is used as a separator on Linux, for windows use ;
Assuming your source files are in src. Assuming you want your compiled classes to be in classes. Assuming your source files reference classes that are in lib/acm.jar:
javac -cp classes:lib/acm.jar -d classes src/com/foo/bar/MyClass.java
will compile the class com.foo.bar.MyClass and put the generated MyClass.class file in classes/com/foo/bar.
You need the acm.jar file in the classpath. That's what the -cp lib/acm.jar option does. You also need classes in the classpath, because MyClass probably references other classes that you have already compiled and that are in your classes directory.
To run your class, it has to be in the classpath, and acm.jar as well:
java -cp classes:lib/acm.jar com.foo.bar.MyClass
As you see, the classpath contains jar files, and directories containing the folder hierarchy which matches the package hierarchy.
I wouldn't use javac from the command line directly, though. Try using a real build tool, that will build all your classes at once, like Gradle or Ant. Maven is also very popular, but I hate it with passion.
I'm trying to compile a java program that is using JavaDB/Derby. On the command line I can run
java org.apache.derby.tools.sysinfo
without errors, but the following line in several of the files causes the error in my question title:
import org.apache.derby.client.am.SqlException;
causes
package org.apache.derby.client.am does not exist
I've done a fresh installation of JavaDB, but I don't think that matters. I've compiled this project once before, and I KNOW I didn't have JavaDB installed. I just had a directory at the top level of the project folder called lib with all of derby's .jar files inside. And I'm pretty sure I didn't have to set any environment variables either.
How can I fix this error? If I need to provide any more information, I will be happy to do so.
I'm using Windows 7 and jdk1.7
Sounds like you have an issue with the JavaDB JARs not being on your classpath. Make sure you specify them using -cp or -classpath on your javac command.