The problem
This is a problem I just faced using makefile in java, on Windows.
I wanted to set up my classpath with multiple path (libraries, etc.). The new command work by hands, but not from the makefile which throws me this error :
javac : no source files
Example
Let's say I have this makefile :
JFLAGS = -g
JARFLAGS = -cvfm
CLASSPATH = ./bin
LIBS = C:/java/lib/mylib.jar
SOURCEPATH = ./src/client
compileAll:
javac $(JFLAGS) -d $(CLASSPATH) -cp $(CLASSPATH)\;$(LIBS) $(SOURCEPATH )/*.java
jar $(JARFLAGS) app.jar bin/client/MANIFEST.MF bin/client/*.class
So the command line to compile the project is :
javac -g -d ./bin -cp ./bin;C:/java/libs/lib.jar ./src/client/*.java
It works well.
The class files goes to ./bin directory. It imports classes from ./bin and the lib.jar library. And it compliles all the source files from the ./src/client directory.
This command works perfectly by hands, but no from the makefile which doesn't compile anything.
Thanks to my text editor which colored the ';' character, I understood that I just needed to escape (disable) the ';' character by using a '\' :
javac -g -d ./bin -cp ./bin\;C:/java/libs/lib.jar ./src/client/*.java
Now, it works well from makefile !
Related
I'm following a guide that only includes compilation instructions on windows. How would one run this build.bat file on Linux?
The batch file looks like this:
#echo off
#echo Compiling...
javac -classpath ..\..\lib\OneWireAPI.jar;%classpath% -d . .\src\*.java
And when I run the javac command on Linux, it fails:
javac -classpath ../../lib/OneWireAPI.jar;%classpath% -d . ./src/ReadTemp.java
The output is:
javac: no source files
What is the correct way to do this?
On Linux, you have to use : (colon) in place of ; (semicolon) as the path separator in Java options.
Also, if you have a classpath variable, in most common Linux shells it is referenced by $classpath rather than by %classpath%
javac -classpath ../../lib/OneWireAPI.jar:$classpath -d . ./src/ReadTemp.java
You have two items that did not get translated correctly from Windows CMD to Unix:
Path separator ; should be :.
Environment variables should be changed from %classpath% to $CLASSPATH format. Note that pretty much everything is case-sensitive in Linux, including environment variable names, and the Java path is traditionally all-caps.
Try
javac -classpath ../../lib/OneWireAPI.jar:$CLASSPATH -d . ./src/ReadTemp.java
I am trying to build a make file for my program and Im getting the error missing operator at line 4 (javac $(JFLAGS)). I am also getting the error "none to do with default". Can someone help me with this error please? i have been stuck for quite a bit. Thank you much
JFLAGS = -g -d
JC = javac
%.class : %.java
javac $(JFLAGS)
CLASSES = \
Hello.java
default: $(CLASSES:.java=.class)
clean:
$(RM) *.class
You mention you are getting the error
make: Nothing to be done for 'default'.
This is not an error. It is make telling you that the target default is up to date and none of its prerequisites are older than it or need to be remade. For your particular case this will occur when the file Hello.class already exists in the same directory as your makefile. It is not an error but a simple message from make.
With regards to your other error
Java: missing operator at line 4
might this possibly say
makefile:4: *** missing separator. Stop.
instead? If that is the case then it means that you have not correctly indented the line
javac $(JFLAGS)
with a tab character.
Note: I mention this because it appears to be the closest error message to what you have described that I can replicate.
Another more pressing issue than the above is in particular your use of javac $(JFLAGS) and JFLAGS. In JFLAGS you have specified the -d option. When you execute javac $(JFLAGS) the error you get should look similar to
$ javac -g -d
javac: -d requires an argument
This is because the -d option when passed to javac is used to tell javac where the output directory that it should place .class files is. If you want your .class files to be output in the same directory as your makefile relative to their package name (see below) then you need to delete the -d option and declare JFLAGS as
JFLAGS = -g
If however, you dont want your .class files to be output in the same directory as your makefile then you need to declare a directory after the -d option in JFLAGS as
JFLAGS = -g -d /path/to/my/output/directory
Now that we've covered the -d option let's move on to actually compiling your .java files. The current rule you have is
%.class : %.java
javac $(JFLAGS)
this should to be altered to
%.class : %.java
$(JC) $(JFLAGS) $<
The automatic variable $< stands for the first prerequisite and will create a command like
$ javac -g Hello.java
for your particular example, which will create a Hello.class file in the same directory as the makefile and your Hello.java file.
I have the .java file on the current working directory but javac reports:
javac: no source files
Usage: javac <options> <source files>
use -help for a list of possible options
I'm working on ubuntu.
From your comment above, it looks like you tried:
javac -cp .;lib.jar a.java on your Ubuntu system. The CLASSPATH separator is : on Unix systems and ; on Windows.
Ubuntu considered the command up to the ;, java -cp . and thus gave the message.
javac -cp .:lib.jar a.java should compile fine.
For anyone who is using powersehll on windows use CLASSPATH separator : instead of ;
I tried a similar thing and found that you need to mention the absolute path when you are using the
-cp and -d option with javac like this
javac -cp 'ur location of jars & files'; -d 'location to add your classes to' 'absolute path of file'
eg:
javac -cp C:\home\lib\mywork; -d c:\home\classes c:\home\files*.java
for javac, there are options and arguments
arg: it takes argument as path of source file
options: we require for basic compilation
-sourcepath: the path of dependent source files
-d: directory path of output classes
javac -sourcepath './src' -d './bin' -verbose './src/App.java'
I'm writing a makefile that compiles a .java file in a different directory, and then I want to run it, without changing directories. I want to do something along the lines of:
$(SQM_JAVA_TOOL_DONE) : $(SQM_JAVA_TOOL)
$(shell cd /home_dir)
javac myjavafile.java
java myjavafile
where the Java file is /home/myjavafile.java, and the makefile isn't running from /home.
How can I do this?
I might be misunderstanding the question, but you can compile with
javac /home/MyJavaFile.java
This will create MyJavaFile.class in /home
You can then run it by including /home on the classpath. e.g.
java -cp /home MyJavaFile
If you want to generate the class file in a different directory then you can use the -d option to javac.
Use the -d command line parameter with javac to tell it what directory you'd like to store the compiled class files in. Then, to run the program, simply include this directory in the classpath:
javac -d some/directory myjavafile.java
java -cp some/directory myjavafile
Just to add to the existing answers, you may want the --source-path flag:
--source-path <path>, -sourcepath <path>
Specify where to find input source files
I believe this effectively sets the package root javac will compile from (i.e. <path> will be stripped from the expected package name of the files). It's still necessary to enumerate the files to compile, and this should still be relative to the current working directory, not the path passed to --source-path.
For example, to compile and run from a project's root where source is stored in src/ and you want it build in bin/:
$ javac --source-path src -d bin src/mypackage/*.java
$ java -cp bin mypackage.Main
This works even from directories elsewhere in the filesystem, e.g.:
$ javac --source-path /some/absolute/path/src -d /some/absolute/path/bin /some/absolute/path/
$ java -cp /some/absolute/path/bin mypackage.Main
I am using VS Code and installed java and code runner extensions. When I created new java project using the extension, it was creating the .class file in src instead of bin. To solve the issue I opened settings.json file from File > Preferences > Settings and searched for "settings" (or "code-runner"). Then I added following lines in that file.
"code-runner.executorMap": {
"java": "cd \"$workspaceRoot\\\" && javac --source-path src -d bin src\\$fileName && java -cp bin $fileNameWithoutExt",
}
If you don`t want to see the command that runs before code file then add these lines instead:
"code-runner.clearPreviousOutput": true,
"code-runner.showExecutionMessage": false,
"code-runner.executorMap": {
"java": "there is && clear added in the execution paramater"
"java": "cd \"$workspaceRoot\\\" && javac --source-path src -d bin src\\$fileName && clear && java -cp bin $fileNameWithoutExt",
}
I hope this finds someone with similar issue.
Really basic question I'm sure for some of you Java heads out there.
I have a list of java files and jars that are required.
On windows to build I have this batch file
javac -cp .;opencsv-1.8.jar;mysql-connector.jar -source 1.4 -target 1.4 *.java
jar cvf cup.jar *.class
del *.class
If I want to do the same thing on mac how would a write a shell script to do the same?
Basically the same thing, except
The path separator is ':' instead of ';'
I believe the command to delete is called 'rm'
Also, I'd put a shabang at the start.
So:
#!/bin/sh
javac -cp .:opencsv-1.8.jar:mysql-connector.jar -source 1.4 -target 1.4 *.java
jar cvf cup.jar *.class
rm *.class