Develop Reference

Java code runs through IDE but fails from terminal

I have a Java Code where I am able to run it on Intellij using custom configuration. The configuration has following attributes :-
module : java 8 (Oracle OpenJDK 1.8.0_321)
classpath : -cp XYZ.main()
main : com.ABC.XYZ.ManageTraffic
CLI arguements : server XYZ.yml
But when I try to run the jar that was build using gradle from terminal , it gives me Error , could not find or load main class com.ABC.XYZ.ManageTraffic
So far I have tried the following things looking at other solutions at Stackoverflow , still getting the same error
java -jar ques.jar
java -jar ques.jar com.ABC.XYZ.ManageTraffic
java -cp /build/libs/ques.jar com.ABC.XYZ.ManageTraffic
Just to cross check , I unzipped the creataed jar and found that com.ABC.XYZ.ManageTraffic class file is available there , still getting error. What could be the issue?

Run it from the IDE, and while it is running, try to get the command used by the IDE from the process list.
not sure what OS you are using but something like this should work on linux/mac:
ps -ef | grep java
After you have the command you can try to understand why its not working for you, or just use that command

Just want to add how I managed to run it. I created a new shaded jar file of the same application. refreshed its dependencies and now it works. I am yet to find out how creating a shaded jar instead of normal jar helped. Right now the only reason I could figure out is there may be version clashes with some dependencies but I wonder how it could throw could not found main class error.
Anyways , then I ran the file with the following command from terminal:
java -jar ./build/libs/ques-shaded.jar server XYZ.yml

Run main of specific class inside a package subdirectory

I am following Scheduled Jobs with Custom Clock Processes in Java with Quartz and RabbitMQ but I struggle to actually run another dyno from withing the jar file packeg by Spring.
In the package (server-1.0-SNAPSHOT.jar) I need to run the company.server.Scheduler. The .class file is in BOOT-INF/classes.
I've tried to do this but I am always getting
Error: Could not find or load main class company.server.Scheduler
I'm struggling to get the syntax right.
So what I need to run is
BOOT-INF/classes/company/server/Scheduler.class
I have tried this:
java -classpath BOOT-INF/classes -jar server-1.0-SNAPSHOT.jar company.server.Scheduler
java -classpath server-1.0-SNAPSHOT.jar:/BOOT-INF/classes company.server.Scheduler
But this either runs the main class from the Manifest or crashes.
Also tried:
java -classpath server-1.0-SNAPSHOT.jar BOOT-INF.classes.company.server.Scheduler
java -classpath server-1.0-SNAPSHOT.jar BOOT-INF/classes/company/server/Scheduler
Try it out ...
git clone https://github.com/silentsnooc/run-scheduler
cd run-scheduler/
mvn clean install
cd target/
java -cp .:scheduler-test-1.0-SNAPSHOT.jar BOOT-INF.classes.Scheduler
If I follow this on Heroku then it should be something like
java -cp scheduler-test-1.0-SNAPSHOT.jar:BOOT-INF/classes/* Scheduler
but it's not working telling me the main class Scheduler could not be found.

Add jar files to classpath at launch time

I want to add some jar files to my binary at runtime, but I keep getting errors. I'm running this on a Windows machine. My code is in a directory called SeleniumTest.
Here is the command I used to compile:
javac SeleniumTest\src\com\src\test\First.java -d SeleniumTest\bin -cp SeleniumTest\lib\junit-4.10.jar;SeleniumTest\lib\selenium-java-2.39.0.jar;SeleniumTest\lib\selenium-server-standalone-2.39.0.jar
This worked successfully. However when I try to run this command:
java -cp SeleniumTest\lib\junit-4.10.jar;SeleniumTest\lib\selenium-java-2.39.0.jar;SeleniumTest\lib\selenium-server-standalone-2.39.0.jar SeleniumTest\bin com.src.test.First
I get a message:
Error: Could not find or load main class SeleniumTest\bin
My code, First.java exists in
SeleniumTest\bin\com\src\test
What am I doing wrong?

try this
java -cp "SeleniumTest\lib\junit-4.10.jar;SeleniumTest\lib\selenium-java-2.39.0.jar;SeleniumTest\lib\selenium-server-standalone-2.39.0.jar;SeleniumTest\bin" com.src.test.First

try following
java -cp SeleniumTest\lib\junit-4.10.jar;SeleniumTest\lib\selenium-java-2.39.0.jar;SeleniumTest\lib\selenium-server-standalone-2.39.0.jar SeleniumTest\bin SeleniumTest\src\com\src\test\First

adding JAR class path in UBUNTU

This is might be a common question but I am not able to add class path for a JAR file in UBUNTU. I have given below all the details I know:
java is located here:
the o/p of which java command is - /usr/bin/java
sudo vim /etc/bash.bashrc
export CLASSPATH=$CLASSPATH:/downloads/aws-java-sdk-1.3.24/lib/aws-java-sdk-1.3.24.jar
ps: downloads folder is directly under the root
sudo vim /etc/environment
CLASSPATH="/usr/lib/jvm/jdk1.7.0/lib: /downloads/aws-java-sdk-1.3.24/lib/aws-java-sdk-1.3.24.jar:"
As you can see, I have added the class path in bashrc and etc/environment... but still I am getting an error while trying to run the S3Sample.java which comes with awssdk for java.
when I compile the java file, I get the following errors:
ubuntu#domU-12-31-39-03-31-91:/downloads/aws-java-sdk-1.3.24/samples/AmazonS3$ javac S3Sample.java
S3Sample.java:25: error: package com.amazonaws does not exist
import com.amazonaws.AmazonClientException;
Now, I clearly understand that the JAR file is not added to the class path and so I am not getting the error. I've also tried javac with the class path option - but it does not work :(
PS: JAVA home is set correctly as other java programs work properly.

To set the classpath, it is in most cases better to use the the -cp or -classpath argument when calling javac and java. It gives you more flexibility to use different classpaths for different java applications.
With the -cp and -classpath arguments your classpath can contain multiple jars and multiple locations separated with a : (colon)
javac -cp ".:/somewhere/A.jar:/elsewhere/B.jar" MyClass.java
java -cp ".:/somewhere/A.jar:/elsewhere/B.jar" MyClass
The classpath entry in the example sets the classpath to contain the current working directory (.), and the two jar files A.jar and B.jar.
If you want to use the CLASSPATH environment variable you can do
export CLASSPATH=".:/somewhere/A.jar:/elsewhere/B.jar"
javac MyClass.java
java MyClass

How to run Java program in command prompt

I created a Java project to call a Web service.
It has one Main java file and another class file.
I have used some jar files for HTTP client.
In Eclipse it runs fine.
I need to run the Java program in command prompt by passing some arguments.
In command prompt I went to src folder containing main java and sub class java file and gave the following command
javac mainjava.java
I'm getting following error
mainjava.java:14: cannot find symbol
symbol : class SubClass
here SubClass is my another java class file used to call the web service.
How to run the program by passing arguments?

javac is the Java compiler. java is the JVM and what you use to execute a Java program. You do not execute .java files, they are just source files.
Presumably there is .jar somewhere (or a directory containing .class files) that is the product of building it in Eclipse:
java/src/com/mypackage/Main.java
java/classes/com/mypackage/Main.class
java/lib/mypackage.jar
From directory java execute:
java -cp lib/mypackage.jar Main arg1 arg2

A very general command prompt how to for java is
javac mainjava.java
java mainjava
You'll very often see people doing
javac *.java
java mainjava
As for the subclass problem that's probably occurring because a path is missing from your class path, the -c flag I believe is used to set that.

You can use javac *.java command to compile all you java sources. Also you should learn a little about classpath because it seems that you should set appropriate classpath for succesful compilation (because your IDE use some libraries for building WebService clients). Also I can recommend you to check wich command your IDE use to build your project.

All you need to do is:
Build the mainjava class using the class path if any (optional)
javac *.java [ -cp "wb.jar;"]
Create Manifest.txt file with content is:
Main-Class: mainjava
Package the jar file for mainjava class
jar cfm mainjava.jar Manifest.txt *.class
Then you can run this .jar file from cmd with class path (optional) and put arguments for it.
java [-cp "wb.jar;"] mainjava arg0 arg1
HTH.

javac only compiles the code. You need to use java command to run the code. The error is because your classpath doesn't contain the class Subclass iwhen you tried to compile it. you need to add them with the -cp variable in javac command
java -cp classpath-entries mainjava arg1 arg2 should run your code with 2 arguments