This question might be related to this and a ton other UnsatisfiedLinkError questions.
I'm trying to run the following code.
import jnr.ffi.LibraryLoader;
import jnr.ffi.types.pid_t;
/**
* Gets the process ID of the current process, and that of its parent.
*/
public class Getpid {
public interface LibC {
public #pid_t long getpid();
public #pid_t long getppid();
}
public static void main(String[] args) {
LibC libc = (LibC) LibraryLoader.create(LibC.class).load("c");
System.out.println("pid=" + libc.getpid() + " parent pid=" + libc.getppid());
}
}
The code compiles correctly but refuses to run,
(compilation step)
javac -cp /usr/share/java/jnr-ffi.jar:. Getpid.java
(running step)
java -cp /usr/share/java/jnr-ffi.jar:. Getpid
While running I get this error.
You need to install objective-web's asm.jar
and jjfi.jar
add those to your classpath and voila!
Compile with this:
javac -cp /usr/share/java/jnr-ffi.jar:.:/usr/lib/java/jffi.jar:/usr/lib/java/jffi-native.jar:/usr/share/java/objectweb-asm/asm.jar Getpid.java
and run with this:
java -cp /usr/share/java/jnr-ffi.jar:.:/usr/lib/java/jffi.jar:/usr/lib/java/jffi-native.jar:/usr/share/java/objectweb-asm/asm.jar Getpid
Related
I'm on windows 10 + jdk1.8
Use used maven to create a project named UseNative, package name is mygroup, files are under:
src\main\java\mygroup\
I have UseNative.java:
package mygroup;
public class UseNative {
public native void greet(String name);
static {
System.loadLibrary("UseNative");
}
#SuppressWarnings("static-access")
public static void main(String[] args) {
System.out.println(System.getProperty("java.library.path"));
new UseNative().greet("me");
}
}
Then under powershell:
javac UseNative.java
OK, and then:
javah -classpath . UseNative
or
javah -classpath . mygroup.UseNative
Both says:
Error: cannot find class file for 'mygroup.UseNative'
I tried to remove the package mygroup line from java file, and then it works! But anyhow, I need this line to comply coding standard.
Where does it get wrong, add additional parameter or environment?
Thanks!
I am trying to run the following method in Loader.java from the command line:
public static void method(String path, String word)
As seen above, I must pass in the variables path and word, and I want the command line to display the System.out.println()'s in the method.
What command can I run to do this?
Note: when I run the following commands,
javac *.java
jar -cvf Loader.jar Loader.class
java -cp ./Loader.jar Loader
I get the following error:
Caused by: java.lang.NoClassDefFoundError: path/to/Loader (wrong name: Loader)
What must I do to successfully run method from the command line?
Here is minimum reproducible version of Loader.java:
public class Loader {
public static void main(String[] args) {
method("my/path", "my_word");
}
public static void method(String path, String word) {
System.out.println("Output after doing something");
}
}
Just do the following:
javac Loader.java
java Loader
In fact, if you are you Java-11 or above, you don't even need to use the first command i.e. you can directly use the following command:
java Loader.java
However, if you want to create a jar file and execute the class from it, execute the steps given below:
mkdir demo
cd demo
Now create/place Loader.java in this folder. Then,
javac *.java
jar -cvf loader.jar .
java -cp loader.jar Loader
Note that I've used a new directory, demo to make it clear but it is not necessary. Another thing you should notice is the . at the end of jar command which specifies the current directory.
How to process command-line arguments?
String[] args parameter in main stores all the parameters from the command-line e.g. if you run the following program as java Loader my/path my_word from the command-line,
public class Loader {
public static void main(String[] args) {
if (args.length >= 2) {
method(args[0], args[1]);
} else {
System.out.println("Command line parameters are missing");
}
}
public static void method(String path, String word) {
System.out.println("Path: " + path);
System.out.println("Word: " + word);
}
}
the output will be
Path: my/path
Word: my_word
I'm executing the programs from command line and using packages in them.
my program file names are TestA.java and TestB.java.
I've executed below initially
javac TestA.java
No issues for the above and it generated the class file as well
for the following i'm observing the issue
javac TestB.java
output :
TestB.java:2: error: '.' expected
import TestA;
^
TestB.java:2: error: ';' expected
import TestA;
^
2 errors
and the TestA.java file is
package a.b;
class TestA {
public static void methodPublic(){
methodPrivate();
}
protected static void methodProtected(){
methodPrivate();
}
static void methodDefault(){
methodPrivate();
}
private static void methodPrivate(){}
}
TestB.java content is :
package a.b;
import TestA;
public class TestB {
public static void main(String args[]) {
TestA.methodPublic();
TestA.methodProtected();
TestA.methodDefault();
}
public static void methodPublic() {
}
protected static void methodProtected() {
}
static void methodDefault() {
}
private static void methodPrivate() {
}
}
I'm executing the javac by navigating to b folder where these two files exist.
I'm executing the javac by navigating to b folder where these two files exist.
You don't want to do that; the fully qualified class name of every class includes the package. They form a tree. Much like your filesystem. From the b folder move up two directories (to the folder containing a - e.g. cd ../.. or cd ..\.. on Windows). Then
javac -cp . a/b/TestA.java a/b/TestB.java
Also, you would normally want that to be written to a "binary" output folder. So
javac -cp . -d bin a/b/TestA.java a/b/TestB.java
Finally, you don't need to import TestA because it is in the same package as TestB. But, if you want to you need
import a.b.TestA;
I am new to Cucumber and trying to solve simple issue:
I have created a Java Project and referred all the cucumber related jars to the build-path of this project (called it "CukeTest4") and below is the structure showing the java file and feature file. When I run this feature file as Cucumber feature in Eclipse, it runs fine.
Now, I would like to run this from another main method. I created another Java Project, Added a Class with main method with code below which is in default package.
import cucumber.api.cli.Main;
public class UseCukeFromMain {
public static void main(String[] args) throws Throwable
{
Main.main(new String[]{"-g", "C:/work/workspaces/neon2_wks_new1/Cuketest4/src/com/cuke", "C:/work/workspaces/neon2_wks_new1/Cuketest4/src/com/cuke/cukefeature.feature"});
}
}
I have provided implementation for the method in the java file as it works fine from Eclipse but shows the message below to implement the method
[33mU[0m
1 Scenarios ([33m1 undefined[0m)
1 Steps ([33m1 undefined[0m)
0m0.000s
You can implement missing steps with the snippets below:
#Given("^I want to write a step with precondition$")
public void i_want_to_write_a_step_with_precondition() throws Throwable {
// Write code here that turns the phrase above into concrete actions
throw new PendingException();
}
I have tried a lot of combination for -g option, but the message is same.
EDIT2
From the comments below, adding the package to glue when the other project is in classpath, works fine.
Main.main(new String[]{"-g", "com.cuke", "C:/work/workspaces/neon2_wks_new1/Cuketest4/src/com/cuke/cukefeature.feature"};
But, Another issue:
I have some old projects that I need to integrate with cucumber. All the .class and .java are present in the folder(NO src or bin directory):
C:\work\RFT_WS2\Cuketest3
, I have this directory in the Classpath. I have tried following option but unable to understand the issue:
-g "" path/to/feature //(NOT WORKING)
-g "classpath:" path/to/feature //(NOT WORKING)
-g "Cuketest3" // Added "C:\work\RFT_WS2" in classpath (NOT WORKING)
Now if I add the .java file to a package say "steps" and have "C:\work\RFT_WS2\Cuketest3" in classpath, option looks like
-g "steps" path/to/feature //(WORKING)
My question is that how to get it to find the methods implementation for a default package.
Also how do add multiple glue option, for example
Not Working cases I tried
Main.main(new String[]{"-g", "com.cuke,com.cuke1", "C:/work/workspaces/neon2_wks_new1/Cuketest4/src/com/cuke/cukefeature.feature"};
Main.main(new String[]{"-g", "com.cuke", "com.cuke1", "C:/work/workspaces/neon2_wks_new1/Cuketest4/src/com/cuke/cukefeature.feature"};
Thanks.
The glue option takes a path value which reflects the package(s) of the glue classes to be included in the classpath.
Find a simplified working example below
Assume following structure
/tmp/cuke-test/features/cukefeature.feature
/tmp/cuke-test/lib
/tmp/cuke-test/project1/src/com/cuke/CukeSteps.java
/tmp/cuke-test/project2/src/UseCukeFromMain.java
cukefeature.feature
Feature: simple test
Scenario: test programatic call of Cucumber
Given we have feature file
When some glue code exists
Then those steps should not fail
lib
cucumber-core-2.1.0.jar
cucumber-html-0.2.6.jar
cucumber-java-2.1.0.jar
cucumber-jvm-deps-1.0.6.jar
cucumber-testng-2.1.0.jar
gherkin-5.0.0.jar
jcommander-1.64.jar
snakeyaml-1.17.jar
tag-expressions-1.0.1.jar
testng-6.11.jar
CukeSteps.java
package com.cuke;
import cucumber.api.PendingException;
import cucumber.api.Scenario;
import cucumber.api.java.Before;
import cucumber.api.java.en.*;
public class CukeSteps {
#Given("^we have feature file$")
public void we_have_feature_file() throws Throwable {
System.out.println("execute Given step");
}
#When("^some glue code exists$")
public void some_glue_code_exists() throws Throwable {
System.out.println("execute Then step");
}
#Then("^those steps should not fail$")
public void those_steps_should_not_fail() throws Throwable {
throw new PendingException();
}
}
UseCukeFromMain.java
import cucumber.api.cli.Main;
public class UseCukeFromMain {
public static void main(String[] args) throws Throwable {
Main.main(new String[]{
"--glue",
"com/cuke", // the package which contains the glue classes
"/tmp/cuke-test/features/cukefeature.feature"}
);
}
}
compile the classes
javac -cp "lib/*" -d project1/bin/ project1/src/com/cuke/*.java
javac -cp "lib/*" -d project2/bin/ project2/src/*.java
run the UseCukeFromMain
The root direcotry which contains the glue classes (project1/bin) must be in the classpath.
java -cp "project2/bin:project1/bin:lib/*" UseCukeFromMain
output
execute Given step
execute Then step
1 Scenarios (1 pending)
3 Steps (1 pending, 2 passed)
0m0.104s
cucumber.api.PendingException: TODO: implement me
at com.cuke.CukeSteps.those_steps_should_not_fail(CukeSteps.java:21)
at ✽.those steps should not fail(/tmp/cuke-test/features/cukefeature.feature:6)
edit Using Step definitions in default package
Assume following structure
features/cukefeature.feature
lib/
project1/src/CukeSteps.java
project2/src/UseCukeFromMain.java
cukefeature.feature
lib/
the same as in the first example
CukeSteps.java
// note: there is no package statement
import cucumber.api.PendingException;
import cucumber.api.Scenario;
import cucumber.api.java.Before;
import cucumber.api.java.en.*;
public class CukeSteps {
#Given("^we have feature file$")
public void we_have_feature_file() throws Throwable {
System.out.println("execute Given step");
}
#When("^some glue code exists$")
public void some_glue_code_exists() throws Throwable {
System.out.println("execute Then step");
}
#Then("^those steps should not fail$")
public void those_steps_should_not_fail() throws Throwable {
throw new PendingException();
}
}
UseCukeFromMain.java
import cucumber.api.cli.Main;
public class UseCukeFromMain {
public static void main(String[] args) throws Throwable {
Main.main(new String[]{
"--glue",
"", // to used Step definitions in default package
"features/cukefeature.feature"}
);
}
}
compile classes
The option -d . creates the class files in the current directory.
javac -cp "lib/*" -d . project1/src/*.java
javac -cp "lib/*" -d project2/bin/ project2/src/*.java
created class files
CukeSteps.class
project2/bin/UseCukeFromMain.class
run the UseCukeFromMain
The current directory is added to the classpath using the ..
java -cp "project2/bin:.:lib/*" UseCukeFromMain
output
execute Given step - default package
execute Then step - default package
1 Scenarios (1 pending)
3 Steps (1 pending, 2 passed)
0m0.096s
cucumber.api.PendingException: TODO: implement me
at CukeSteps.those_steps_should_not_fail(CukeSteps.java:19)
at ✽.those steps should not fail(features/cukefeature.feature:5)
edit Using Step definitions from different packages.
Assume following structure
features/cukefeature.feature
lib
project1/src/com/cuke1/CukeStepsB.java
project1/src/com/cuke/CukeStepsA.java
project2/src/UseCukeFromMain.java
cukefeature.feature
lib/
the same as in the first example
The Step definitions are split in two classes, in different packages
CukeStepsA.java
package com.cuke;
import cucumber.api.PendingException;
import cucumber.api.Scenario;
import cucumber.api.java.Before;
import cucumber.api.java.en.*;
public class CukeStepsA {
#Given("^we have feature file$")
public void we_have_feature_file() throws Throwable {
System.out.println("execute Given step - package com.cuke");
}
}
CukeStepsB.java
package com.cuke1;
import cucumber.api.PendingException;
import cucumber.api.Scenario;
import cucumber.api.java.Before;
import cucumber.api.java.en.*;
public class CukeStepsB {
#When("^some glue code exists$")
public void some_glue_code_exists() throws Throwable {
System.out.println("execute Then step - package com.cuke1");
}
#Then("^those steps should not fail$")
public void those_steps_should_not_fail() throws Throwable {
throw new PendingException();
}
}
UseCukeFromMain.java
import cucumber.api.cli.Main;
public class UseCukeFromMain {
public static void main(String[] args) throws Throwable {
Main.main(new String[]{
"--glue",
"com/cuke",
"--glue",
"com/cuke1",
"features/cukefeature.feature"}
);
}
}
compile classes
javac -cp "lib/*" -d project1/bin/ project1/src/com/cuke/*.java project1/src/com/cuke1/*.java
javac -cp "lib/*" -d project2/bin/ project2/src/*.java
created class files
project1/bin/com/cuke1/CukeStepsB.class
project1/bin/com/cuke/CukeStepsA.class
project2/bin/UseCukeFromMain.class
run the UseCukeFromMain
java -cp "project2/bin:project1/bin:lib/*" UseCukeFromMain
output
execute Given step - package com.cuke
execute Then step - package com.cuke1
1 Scenarios (1 pending)
3 Steps (1 pending, 2 passed)
0m0.114s
cucumber.api.PendingException: TODO: implement me
at com.cuke1.CukeStepsB.those_steps_should_not_fail(CukeStepsB.java:16)
at ✽.those steps should not fail(features/cukefeature.feature:5)
The absolute path is required for feature file. The step def directory requires classpath format.
public static void main(String[] args) throws Throwable {
//Your code to get feature file full path
Main.main(new String[]{"-g", "classpath to step definition file", "Full path to feature file"});
}
Is there a way to print within a Java Code the libraries that has been imported, and available during the execution?
For example :
import javax.swing.JFrame;
public class Main {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
//some code
}
}
I need to print javax.swing.JFrame.
If you need the actual imports used in your source code (rather than using the information in the bytecode), you can use a library called QDox which will parse your source code and can get a list of the imports you use:
Main.java
import com.thoughtworks.qdox.JavaDocBuilder;
import javax.swing.JFrame;
public class Main {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
JavaDocBuilder java = new JavaDocBuilder();
java.addSourceTree(new java.io.File("."));
for (String i : java.getClassByName("Main").getSource().getImports()) {
System.out.println(i);
}
}
}
Compile and run with:
# If you don't have wget, just download the QDox jar by hand
wget -U "" http://repo1.maven.org/maven2/com/thoughtworks/qdox/qdox/1.12/qdox-1.12.jar
javac -classpath qdox-1.12.jar Main.java
java -classpath qdox-1.12.jar:. Main
The output is:
com.thoughtworks.qdox.JavaDocBuilder
javax.swing.JFrame
I don't think that there is a way to do that. Imports are only a syntactic aid for the programmer and are not reflected in the compiled class files. Anyway, what do you need such a feature for?