I am somewhat new to RubyMine but here is my problem. I have a JRUBY Class that I want to extend from a Java class. My Java class is part of a submodule I have imported using git. This is my project structure:
src --> Submodule --> <Directories> --> ClassIWantToExtend.java
--> Ruby Code --> <Directories> --> JRubyClassThatExtendsJava.rb
However, when using RubyMine I have been unable to figure out how to extend this Java class. It can't seem to find it. My current class is blank. This is all I have:
require 'java'
class JRubyClassThatExtendsJava
end
I have tried using '<' and 'include' but when autofilling RubyMine can't seem to find my Java Class. I did just add the submodule using a CLI Git Command. Is it possible I have to add something for RubyMine to see it?
Thanks for any help in advance.
RubyMine, as far as I know (bought a license but never actually used it due this) does not include support for .java (not even a syntax highlighter) - the motivation seems to be that they have a separate product that is a Java IDE. thus this answer is not going to be RubyMine specific :
first you'll need to compile the .java sources and either pack them in a .jar or simply keep in mind what directory the .class files are (javac -d OUT_DIR)
than in your .rb you can either require 'path/to/packed.jar' or simply $CLASSPATH << 'path/to/classes/OUT_DIR'
... than you should be able to load the Java class and extend it in Ruby
Related
I'm a n00b coder. I found an interesting library and trying to start toying with it. Which is not going great. This library is from 99' and uses JUnit (which I'm unfamiliar with) so there is a lot of confusing stuff. But it seems like the source of my failing even more elementary. Namely I have troubles importing packages.
This library has a test called StandardEvalTest.java. I moved to it to main Java directory and now I'm trying and failing to launch it using JUnit.
This package path org.pokersource.game.Deck goes directly from the directory where the test StandardEvalTest.java sits.
I also added the main java directory to the PATH environmental variable. Which as I assumed will allow import to locate the package.
None of those two things help. Also I was suspecting that maybe Deck.java and Deck.class are not enough and I have to do some work to create a package from it. But as far as I can say from Oracle doc the only thing needed is a package name in the header. Which seems to be present.
So I'm out of moves. Please help!
PS: Some additional info inspired by #Dhrubo 's answer:
The test I'm trying to run indeed sits in the main java folder of the library. (I moved it here hoping that when running from here it would be easier to find the package)
If I'm trying to compile the test instead of running it with JUnit he seem to fail to find JUnit classes and other JUnit related stuff.
[Oh OK I'm an idiot! Dont't mind me]
You should include the package while running StandardEvalTest.java as below
javac -cp [classpath] org.pokersource.game.StandardEvalTest.java
and run it from package root directory, I am assuming it is custom java file that you want to compile. You run directory should be parent of your package directory.
** I also see, you are trying to compile StandardEvalTest.java instead of Deck.java ... then check your StandardEvalTest.java file whether it exists in desired location.
I am learning Java on Visual Studio Code. I have installed the "Microsoft extension for Java" in it. My basic Java programs runs fine without package declaration. But I would like to package my program. How ?
Earlier I used "IntelliJ IDEA". I used to start a New Project and declare "package com.java.learn". In Visual Studio Code there is no option to create New java Project. There is an option to create Workspace but I still have the same issue.
I have two java class. "Index.java" & "InputHelper.java". Index.java is the main java file. InputHelper is a seperate class which I use in Index.java. I want to make a project and package both ( or more ) files.
Error Message:
The declared package "com.java.learn" does not match the expected package
A package is a path of subdirectories. Say your java sources are in (subdirectory of) a directory src. All sources immediately under src have the "default" package = no package declaration.
In src/com/java/learn (4 nested directories) the package com.java.learn; is expected for java sources.
In your case create a path of 3 directories: com, java, and learn the latter containing your java source.
For the rest, try to follow the coding conventions of java: class names starting with a capital like Index, variable and method names with a small letter.
In fact though Microsoft is often underestimated, I would chose a more mainstream IDE for learning java. IntelliJ IDEA (Community edition) is fine; NetBeans IDE is a clean an nice IDE too; eclipse is used very often - though a bit overdone IMHO.
I faced a similar issue, coming from Eclipse/IDEA background you find it difficult to not have a feature in your java IDE to create a new package.
Although, Joop Eggen's answer is correct that package is a path of subdirectories but you might find it tedious to create subdirectories when the number of sub packages is greater and name of sub packages is long.
You can use the below VSCode extension :
https://github.com/jiangdequan/vscode-java-saber
It is a very handy extension.It provides support for:
New: Java files(annotation/class/interface/enum/package/JSP/HTML)
Generate Getters and Getters
Copy Qualified Name
Sort Project By Name
Run Maven Goals
Generate Docs
You can try this extension.
You can use Java Projects panel to create a new project, package, class.
Also I think there's an issue in VSC 1.63.2, because a new item is created but it's not displayed in project structure until I reload VSC window.
Another option is to put right package declaration on the first line of a class file and use inline š”light bulb button to move that class to the package it belongs.
P. S. I'm learning Java now so I could be missing something
I would like to get deeper understanding on how Java deals with different versions of Classes/Packages/etc., but couldn't find any resources or at least the best way to google for it. The problem is as follows.
Imagine we have some external package com.external.package that contains a definition of SomeInterface.
Now I write a java class MyClass that implements SomeInterface, and using com.external.package v1.0.0. Next I package a (lean) jar containing MyClass.
Now I plug this jar in another program that is looking for implementations of SomeInterface, but in it's dependencies, it is using com.external.package v2.0.0.
Is the reason I get Failed to find any class that implements SomeInterface that versions of SomeInterface don't match in the program and in the jar that contains a class extending it?
Basically the question I would like to find an answer for is what info do jars store regarding external dependencies? Does it store the exact versions of them and if they don't match at the runtime it complains? But why does it even allow running the program with references to same dependency, but different versions?
Is the reason I get Failed to find any class that implements SomeInterface that versions of SomeInterface don't match in the program and in the jar that contains a class extending it?
There is no "versioning" happening here. Simply, the error states no such class exists on the classpath. For example, you didn't put a -cp in your java command to add that extra JAR/class file.
Other reasons this could happen is that an API marks a class as deprecated in v1, then decides to remove it from v2. In which case, you best try to compile and test your code against the proper library versions before you package your own code. If you made an uber JAR, the classes should get shaded, and you probably wouldn't have missing classes.
Maven projects do have the concept of transitive, versioned dependencies, but you've not said anything about that
Seeing that the original question has found an answer already, it seems somewhat relevant to mention that Java Packages and JARs could be used for specifying package version information as discussed in the following documentation:
https://docs.oracle.com/javase/8/docs/technotes/guides/versioning/spec/versioning2.html#wp89936
Also, the Oracle Java Tutorials discuss them and further concepts around deployment of programs as JAR Files as documented here:
https://docs.oracle.com/javase/tutorial/deployment/jar/index.html
I am working with ForgeGradle (Minecraft Forge modding platform).
I'd like to obfuscate my mod before publishing but the nature of Forge platform won't allow me to do it by simply running program like ProGuard after compilation (with defined libraries).
Why?
The structure goes like this:
Mod -> Forge -> Minecraft
Since Minecraft uses its own obfuscated classes and ForgeGradle compilator is not DIRECTLY obfuscating Mod's code to fit with Minecraft's one, it is not possible to use MC.jar as library while using ProGuard. Compiled Forge Mod is actually decoded by Forge in runtime using SRG names. The logic behind this is not easily explainable so I'll just note: I cannot obfuscate .jar in a way to fit with libraries.
So I though - I could just take my mod's code (.java files) and rename all fields/methods/classes that are MINE before Forge compilation.
Is there a software that would allow me to pick number of .java files and "obfuscate" them in a way to not reaname references that don't belong to them?
EDIT (more explanation):
Mod's code has 3 states: Development, Compiled, Running.
I will try to give an example:
Let's say there is a decompiled method ItemSword.onHit() inside Minecraft.jar
And its compiled (obfuscated) version look like this: bca.aa(), also all packages are lost (flattened).
In mod's development state of code (.java) to make reference to it we simply make: ItemSword.onHit()
When we compile mod the call will look like this (.class): ItemSword.func_ab4234() - this is the SRG I was talking about.
Now when the mod will be loaded to game, forge will translate "ItemSword" to "bca" and "func_ab4234()" to "aa()"
Because of this I can't even add proper library - there IS NONE. I will always get (in ProGuard) NoClassDefFound Warning and I can't ignore it (it will crash compilation).
So after this edit - Is it still possible to make obfuscation with ProGuard (considering I cannot have "good" library assigned)?
Did you try the proguard options?
http://proguard.sourceforge.net/manual/usage.html
e.g. for Serializable classes and other stuff put this to your proguard configuration (you also can preserve complete classes if you like):
<!-- With this code serializable classes will be backward compatible -->
<keepnames implements="java.io.Serializable"/>
<!-- or for native access:-->
<keepclasseswithmembernames>
<method access="native"/>
</keepclasseswithmembernames>
<!--Preserve all public classes, and their public and protected fields and methods.-->
<keep access="public">
<field access="public protected"/>
<method access="public protected"/>
</keep>
If I got your question, you want to obfuscate your own code, not anything beyond that. That's what ProGuard is actually quite good at. Let's assume you created your classes in the packages com.foo and com.bar. You can use this simple ProGuard command to only obfuscate your own classes:
-keep class !com.foo.**,!com.bar.** { *; }
It tells ProGuard to not obfuscate any members of classes which do not belong to either com.foo or com.bar.
If you are getting NoClassDef errors, you added the wrong library. I guess you are using some kind of IDE (perhaps eclipse). Have a look at the libraries your project references to find the correct library classpath (e.g. a jar file). You basically need to find the classpath used for compiling your code, ProGuard will take that as well and everything should work.
I want to develop a web application (no frameworks) mixing java with groovy. I am using the IDE Netbeans with the plugin.
If I start a new Java SE project and add a groovy class, it works with no problems.. but when I create a new java EE project and add a groovy class it can't compile and shows me the following error:
/home/webcodei/NetBeansProjects/testeGroovyWeb/src/java/pacote/Hello.java:23: cannot find symbol
symbol : class Hroovy
location: class pacote.Hello
Hroovy h = new Hroovy();
/home/webcodei/NetBeansProjects/testeGroovyWeb/src/java/pacote/Hello.java:23: cannot find symbol
symbol : class Hroovy
location: class pacote.Hello
Hroovy h = new Hroovy();
2 errors
/home/webcodei/NetBeansProjects/testeGroovyWeb/nbproject/build-impl.xml:383: The following error occurred while executing this line:
/home/webcodei/NetBeansProjects/testeGroovyWeb/nbproject/build-impl.xml:211: Compile failed; see the compiler error output for details.
FALHA NA CONSTRUĆĆO (tempo total: 0 segundos)
Does anybody have a clue of how do I enable Java EE + Groovy in netbeans?
ps: I know the existence of Grails
ps2: The Groovy jar is in my classpath.
Thank you for all!
It appears that the NetBeans 6.5 Java Webapp project manager does not have the "Enable Groovy" support that is present in the Java App and Java Class library projects.
I can think of two ways you might get around this:
First, you could put your Groovy code and tests in a separate project as a Java Class Library. Then make the Java webapp dependent on the Groovy project. NetBeans will build the dependent project automatically so you'll hardly notice they are in separate projects.
Second, the "Enable Groovy" isn't magic. All it does is write a groovy-build.xml in /nbprojects and modify build-impl.xml to import it. The groovy-build.xml overrides the default "javac" macro to invoke "groovyc" instead. If you're at all handy with Ant, you could copy a groovy-build.xml from a Java Application project and copy it to your Java Web project and then import it from your build.xml (before build-impl.xml is imported). The groovy-build.xml would likely need a few tweaks as some of the properties between a webapp and class library are a little different.
#Dave Smith,
This was exactly what I did. I created one javase project and one webapp and started to compare them. After a few minutes I realised that the only diference was the groovy-build.xml.
So I copied the groovy-build.xml into the dir, and inserted the following lines into my build.xml:
<import file="nbproject/groovy-build.xml"/>
Right before the regular
<import file="nbproject/build-impl.xml"/>
And then called the groovy file to overwrite the -init-macrodef-javac.
<target depends="-groovy-init-macrodef-javac" name="-pre-compile">
</target>
I also needed to change the namespace from the groovy-build.xml to mine ex:
<macrodef name="javac" uri="http://www.netbeans.org/ns/web-project/2">
And inserted the j2ee classpath (${j2ee.platform.classpath}) to the attribute a few lines later:
<attribute default="${javac.classpath}:${j2ee.platform.classpath}" name="classpath"/>
After that the project worked successfully! =D
Thank you for all!