Develop Reference

Why does CMD not recognize the javadoc command?

I installed JDK on windows 10, 64bit, followed the documentation instructions.. CMD does not recognize javadoc command. What I tried:
-copied the path of the "bin" folder from Java and in cmd I wrote the command:
set path = "full_path_to_java_sdk_bin_folder"
I saw this on youtube and it worked for the guy, my cmd still did not recognize javadoc command -I set the PATH in system variables from control panel->system->advanced->environment variables and made sure that there are is no other bin folder...
Didn't find any other tips online...

The usual approach for Java development is to set a JAVA_HOME environment variable, and use that to update the PATH (for one thing, it makes it much easier to support multiple versions of Java). Also of note is that Windows puts the quotes oddly on the command line (oddly compared to every other platform that is) and if your path contains spaces you need to quote it correctly. Like,
set "JAVA_HOME=<full_path_to_jdk>"
set "PATH=%JAVA_HOME%\bin;%PATH%"

Java application does not use the right PATH environment variable

I've been struggling to find a reason why my Java application does not use the default PATH environment variable. I need it to launch another program with ProcessBuilder. Right now I get "Cannot run program "..." error=2, No such file or directory", though I can run this program from the terminal. I'm using JDK 1.8, Netbeans 8.1, OS X.
Here's the output of System.out.println(System.getenv("PATH"));:
/usr/bin:/bin:/usr/sbin:/sbin
The actual value of PATH in the terminal (using echo $PATH) is much longer and contains the paths to the desired executables.
I found some questions treating on the same subject but none could help me with this.
Any help appreciated!

PATH is created by whatever shell you're running, but ProcessBuilder does notrun within a shell and therefore there isn't a PATH to attach to, to resolve your program names. You can provide an environment to ProcessBuilder, but don't believe it's going to let you find your program that's in the PATH. In a project of mine I had to provide a fully-qualified path.]
[NOTE: Mileage may vary, I seem to remember having somewhat different results between Windows and *nix, and between different *xix.]

using evosuite from command line

When I try to use the EvoSuite testing tool from the command line, I get the following error:
Fatal crash on main EvoSuite process. Class using seed 1428172877144. Configuration id : null
java.lang.RunTimeExceptionConfiguration:Did not manage to automatically find tools.jar. Use –Dtools_jar_location = <path> properly
at org.evosuite.runtime.agent.ToolsJarLocator.getLoaderForToolsJar<ToolsJarLocator.java:71> ~[evosuite-0.1.1.jar:na]
at org.evosuite.Evosuite.parseCommandLine<Evosuite.java:152> ~[evosuite-0.1.1.jar:na]
at org.evosuite.Evosuite.main<Evosuite.java:304> ~[evosuite-0.1.1.jar:na]
Could someone help me with this?

Make sure you use your JDK to run Evosuite, not the JRE. That may mean either going into the JDK /bin dir and running from there or fully quantifying the executable java binary file when you run (JDK..../bin/java.exe on windows for example).

Copy the tools.jar from JDK to your JRE lib folder...it worked for me..The problem, its not able to find the tools.jar.

As pointed out by Makoto, you need to use a -D option. Note: no space between variable name and assigned value, ie -Dx=v is OK, whereas -Dx = v is wrong. So:
java -jar evosuite-0.1.1.jar -Dtools_jar_location="C:\Program Files\Java\jdk1.7.0_75\lib"

Raspbian/Java: Classpath and MySQL, working in Windows and not on Pi

I know this question has been asked/answered several times, but I still couldn't find a solution to this ClassNotFoundException error, because it works on my computer but not on my RasPi (on which I installed OpenJDK7).
My application uses JDBC to access a MySQL database, and that's the main problem. As has been pointed out on lots of websites ([1], [2], [3]), this is, unfortunately, a common problem.
So, I'm using the mysql-connector-java-5.0.8.jar as a driver. My folder structure is something like /src/de/web/project/ I'm calling the main method via java de.web.project.WakeOnLan (which is the main class that starts all other classes etc.) I got the common ClassNotFound exception and therefor added the -cp parameter so I called the project via java -cp .;mysql-connector-java-5.0.8.jar de.web.project.WakeOnLan to add the driver to classpath.
This worked nicely on my Windows computer from command line, but now I want to push this code to my Raspberry Pi and execute it there. As I said, I installed OpenJDK7 there (using apt-get, if this should be important), used SFTP to upload the folder structure and the code to /home/pi/java/ where there is also the ejre1.7.0_10 folder (so the code is now actually in /home/pi/java/de/web/project/).
I now went back to /home/pi/java and entered java -cp .;mysql-connector-java-5.0.8.jar de.web.project.WakeOnLan as I did on my Windows computer, but it refuses to work (I've put the connector in any folder on the way, just in case). When I call this function, I get a long list of hints Java wants to give me which parameters are allowed for java, finally stating: -bash: mysql-connector-java-5.0.8.jar: command not found. I also tried to turn ".;mysql..." around to "mysql...;." which didn't work as well. If I don't include the -cp parameter, my program says "Thread started" and in the next line: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver etc., so the program does indeed start and writes "Thread started" to System.out.
For some reason, it looks like Java on the Pi ignored the second value of the classpath parameter for which I don't see a good reason.

You might just have problem in classpath setting, there is difference for windows and linux
The classpath syntax is OS-dependent. From Wikipedia :
Being closely associated with the file system, the command-line
Classpath syntax depends on the operating system. For example:
on all Unix-like operating systems (such as Linux and Mac OS X), the
directory structure has a Unix syntax, with separate file paths
separated by a colon (":").
on Windows, the directory structure has a Windows syntax, and each
file path must be separated by a semicolon (";").
This does not apply when the Classpath is defined in manifest files,
where each file path must be separated by a space (" "), regardless of
the operating system.

Mac User - How do I set CLASSPATHS in Mac (I'm working on a Lucene Demo)

I'm trying to get my Apache Lucene demo to work and I'm down to setting the classpath in this tutorial http://lucene.apache.org/java/2_3_2/demo.html
I've hunted the web and these wer the 2 solutions I found to set CLASSPATH:
CLASSPATH=${CLASSPATH}:/Users/philhunter/Desktop/COM562\ Project/lucene-3.0.3/lucene-core-3.0.3.jar
and
setenv CLASSPATH ${CLASSPATH}:/Users/philhunter/Desktop/COM562\ Project/lucene-3.0.3/lucene-core-3.0.3.jar
The second one brings up a error
-bash: setenv: command not found
The first one seemed to accept ok but wen i tried the next step in the tutorial i got an error. The next step was to run the following:
Phil-hunters-MacBook:webapps philhunter$ java org.apache.lucene.demo.IndexFiles /Users/philhunter/Desktop/COM562\ Project/lucene-3.0.3/src
which gave me the error:
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/lucene/demo/IndexFiles
This leads me to believe my CLASSPATHS didnt set correctly. Would I be right in assuming this? I have tried other tutorials and demos and see to get this same error quite a bit. Im new to Lucene and relatively new to mac and Unix shell scripting. Anyone know if I am setting the CLASSPATH correctly and if thats the cause of the errors?

in the terminal type
$ vim ~/.bash_profile
edit the file and add one line:
export CLASSPATH=${CLASSPATH}:/usr/local/lucene-3.6.2/lucene-core-3.6.2.jar:/usr/local/lucene-3.6.2/contrib/demo/lucene-demo-3.6.2.jar;
make sure to change the path of yours.
In your way you lose to add lucene-demo-3.0.3.jar in your classpath.

When you set an environment variable like CLASSPATH then by default it only applies to the current process (i.e. the shell process itself) - it isn't available to the java process you launch in the next line. In order to make it available to other processes you need to "export" the variable. In this case you can use something like:
export CLASSPATH=${CLASSPATH}:/Users/philhunter/Desktop/COM562\ Project/lucene-3.0.3/lucene-core-3.0.3.jar
This basically says "set the CLASSPATH variable to its current value plus the location of the lucene jar, and make the new variable available to any processes launched from this shell".
However, with java the usual way of setting the classpath is to do it as part of the java command itself, using the -classpath or -cp options. In your case it would look something like:
Phil-hunters-MacBook:webapps philhunter$ java -cp /Users/philhunter/Desktop/COM562\ Project/lucene-3.0.3/lucene-core-3.0.3.jar org.apache.lucene.demo.IndexFiles /Users/philhunter/Desktop/COM562\ Project/lucene-3.0.3/src
As an aside, the error you see when using the setenv line is because setenv is the command used in the C shell to set environment variables, but the default Mac shell (and the shell you're using) is bash which doesn't recognise setenv and lets you know it doesn't recognise it with the error message: -bash: setenv: command not found.

i create a .bash_profile file in my home directory and do things like
export GRAILS_HOME=/usr/share/grails
...
export PATH=${GRAILS_HOME}/bin:${GROOVY_HOME}/bin:/usr/local/mysql-5.1.45-osx10.6-x86_64/bin:${PATH}
you can work of that to set the classpath -- these examples show how to declare an environment variable and how to use the variable in other variables.