How to change path while running java file? - java

I am trying to run a java file through another java program . this is my code:
private static void printLines(String name, InputStream ins) throws Exception {
String line = null;
BufferedReader in = new BufferedReader(
new InputStreamReader(ins));
while ((line = in.readLine()) != null) {
System.out.println(name + " " + line);
}
}
private static void runProcess(String command) throws Exception {
Process pro = Runtime.getRuntime().exec(command);
printLines(command + " stdout:", pro.getInputStream());
printLines(command + " stderr:", pro.getErrorStream());
pro.waitFor();
System.out.println(command + " exitValue() " + pro.exitValue());
}
public static void main(String[] args) {
String[] credentials=new String[4];int k=0;
for (String s: args) {
System.out.println(s);
credentials[k]=s;k++;
if(k==4)
break;
}
try {
//runProcess("javac test2.java");
runProcess("java test2 "+credentials[0]+" "+credentials[1]+" "+credentials[2]+" "+credentials[3]+" ");
} catch (Exception e) {
e.printStackTrace();
}System.out.println("hI");
}
The problem is I have kept both the files(which I execute and the one which is executed by that file) in same folder but when I run this file it displays class not found error.. for test2.java and it probably due to the fact that it searches the class file test2.class in some other folder . what should I do?
my file structure:
x/y/Laj.java
x/y/test2.java
and it seaches the class file in x folder?

Use
Runtime.getRuntime().exec(command, null, workingDir);
where workingDir is :
workingDir- the working directory of the subprocess, or null if the subprocess should inherit the working directory of the current process.

If you run the first program using
java x.y.Laj
then you should change the line where you compose the command:
runProcess("java x.y.test2 "+credentials[0]+...
** Later **
Since the x.y is just a red herring, try setting the system property:
runProcess("java -Djava.class.path=\"/.../x/y\" " + credentials[0]+...
For production (start of Laj not from an IDE) consider setting CLASSPATH so that all class files can be found via the class path.

Related

Error Could not find or load main class -jar

I am working on a java UNO project, OS : Ubuntu 14. I am calling exec via passing command to run via a jar file with some set of sub commands of that jar file.
String finalOutputMSG = "";
String[] cmd = {JAVA_LOCATION, " -jar ", JAR_LOCATION, " " + inputFile, " -dir ", ".isc", " -out xml"};//java location provides java location, jar location provides jar location, inputfile contains input file's location -dir provides output directory with name .isc, -out is output file with file format for output is xml
Similar command ran properly without showing any errors but in a case where I am trying to import a file and convert it into another format eg .xlsx to .xml, is giving error. In commands it worked, I have already generated outputs from an input file.
finalOutputMSG = exec(cmd);
/**
* exec() is executed and outputs are displayed
*
* #param String[] command passed to jar
* #return output message containing outputs or output message
*/
private static String exec(String[] cmd) {
String outputMSG = "";
Process proc = null;
try {
ProcessBuilder pb = new ProcessBuilder(cmd);
pb.redirectErrorStream(true);//any error output generated by subprocesses merged with the standard output,
//read using the Process.getInputStream()
///* Start the process */
proc = pb.start();
if (debug) {
System.out.println("Process started !");
}
outputMSG = getOutput(proc);
if (debug) {
System.out.println("outputMSG " + outputMSG);
}
} catch (IOException e) {
if (debug) {
System.out.println("Exception in exec " + e.getMessage());
JOptionPane.showMessageDialog(null, "Exception in exec ");
}
// StringBuilder append = appendToFile.append("Exception in exec ").append(e.getMessage());
} catch (Exception e) {
if (debug) {
System.out.println("Exception in exec " + e.getMessage());
JOptionPane.showMessageDialog(null, "Exception in exec ");
}
} finally {
///* Clean-up */
proc.destroy();
if (debug) {
System.out.println("Process ended !");
}
}
return outputMSG;
}
/**
* Reads output from current process
*
* #param current process
* #return output read in current process
*/
private static String getOutput(Process p) {
StringBuilder outStream = new StringBuilder();
if (debug) {
System.out.println("StringBuilder initialized in getOutput");
}
try {
BufferedReader in = new BufferedReader(new InputStreamReader(p.getInputStream()));
if (debug) {
System.out.println("BufferedReader initialized in getOutput");
}
String line = null;
if (debug) {
System.out.println("in.readLine() in getOutput abt to be read");
}
while ((line = in.readLine()) != null) {
outStream.append(line);
if (debug) {
System.out.println("line in getOutput " + line);
System.out.println("outStream in getOutput " + outStream);
}
outStream.append("\n");
}
} catch (IOException e) {
if (debug1) {
System.out.println("IOException in getOutputs " + e.getMessage());
}
} catch (Exception ex) {
if (debug1) {
System.out.println("Exception in getOutputs" + ex.getMessage());
}
}
return outStream.toString();
}
Error Message depicted by Netbeans
Error: Could not find or load main class -jar
I have searched on the issue, but could not find any help that is useful, I could not understand, what is missing.
Solution:
String[] cmd = {JAVA_LOCATION, " -jar ", JAR_LOCATION, " " + inputFile, " -dir ", ".isc", " -out xml"};
I replaced the values that printed in console, and ran the command so got on terminal, it worked fine.
Solution: the command to be used must be without any spaces in the ends. Because terminal in linux interprets the commands like for "ls", but in java/ any programming language, it doesn't interprets for ls, so in case of the following parameter cmdarray
public Process exec(String[] cmdarray)
throws IOException
takes the command as it is.
String[] cmd = {JAVA_LOCATION, "-jar", JAR_LOCATION, inputFile, "-dir", ".isc", "-out", "xml"};

Running multiple Batch files from different threads Java

I have n number of thread getting created at run time according to the input source files present in a folder. For every thread, I have one common class which has all the functions present that are used by every thread. Every thing is working perfectly except the part where batch files are run.
I have main class which is creating thread(which is working perfectly fine). Then I am creating batch files with relevant contents( which is also running perfectly). After that, only 1(can be anyone, no specific pattern) thread is able to execute the batch file and not the others.
Code:
String batch_content = "echo off \n "
+ "powershell.exe -file "
+ utility_path + "convertCSVSwiss.ps1 " + fpath + filename + " -executionpolicy Unrestricted \n ";
String batch_name = "batch_" + fname +"_"+sdf.format(cal.getTime())+ ".bat";
Utils.createBatchFile(batch_content, bat_file_path, batch_name);
Utils.RunBatch(bat_file_path, batch_name,csv_file_path,fname);
Utils.createBatchFile is working fine which create a batch file with the batch content. But Utils.RunBatch seems to having some problem. Here is the code for RunBatch:
public static void RunBatch(String filepath, String filename,String csv_file_path,String fname) throws Exception {
try {
System.out.println("Started Program");
new File(csv_file_path + "\\" + fname).mkdir();
String filePath1 = filepath + filename;
System.out.println("Batch file running is " + filePath1);
Process p = Runtime.getRuntime().exec(new String[] { "cmd.exe", "/c", filePath1 });
p.getOutputStream().close();
p.waitFor();
} catch (Exception e) {
e.printStackTrace();
}
}
My log file prints this:
Batch file running is C:\ER\ETL\bat files\batch_Sample_Data_10_40_16_12_40_37.bat
Batch file running is C:\ER\ETL\bat files\batch_ssd_10_40_16_12_40_37.bat
but it runs only the first one.
Any help would be appreciated.
P.S I am sorry if I missed any information that may be necessary to get this problem resolved. Please let me know and I can then edit my post.
EDIT:
Here is my code.
//main class to start new thread for every excel file present in the source directory
public class LoadData{
public static void main(String[] args) throws Exception{
try{
File folder = new File(fpath);
File[] listoffiles = folder.listFiles();
for (int i = 0; i < listoffiles.length; i++) {
if (listoffiles[i].isFile()) {
filename = listoffiles[i].getName();
c = filename.lastIndexOf(".");
absfilename = filename.substring(0, c);
System.out.println("File name with extension is "+filename);
System.out.println("File name is "+absfilename);
System.out.println("Starting thread for "+absfilename);
ConvertToCSV et = new ConvertToCSV();
et.fpath = fpath;
et.utility_path=utility_path;
et.filename=filename;
et.fname = absfilename;
et.bat_file_path =bat_file_path;
et.tpath =tpath;
et.csv_file_path=csv_file_path;
Thread t = new Thread(et);
t.start();
}
}
}
catch (Exception e) {
e.printStackTrace();
}
}
}
//class to create the batch file content
public class ConvertToCSV implements Runnable{
String fpath,utility_path,filename,fname,bat_file_path,tpath,csv_file_path;
try{
String batch_content = "echo off \n "
+ "powershell.exe -file "
+ path_to_powershell_script_to_convert_excel_into_csv + "convertCSVSwiss.ps1 " + path_and_name_to_the_excel_file " -executionpolicy Unrestricted \n ";
String batch_name = "batch_" + excel_file_name +"_"+sdf.format(cal.getTime())+ ".bat";
Utils.createBatchFile(batch_content, bat_file_path, batch_name);
Utils.RunBatch(bat_file_path, batch_name,csv_file_path,fname);
}
catch (Exception e) {
e.printStackTrace();
}
}
public class Utils{
//function to create the batch file
public static void createBatchFile(String batch_content, String path, String batch_name) throws IOException {
String p = path + batch_name;
File batfile = new File(p);
FileWriter fw = new FileWriter(batfile);
fw.write(batch_content);
fw.close();
}
//function to run the batch file
public static void RunBatch(String filepath, String filename,String csv_file_path,String fname) throws Exception {
try {
System.out.println("Started Program");
new File(csv_file_path + "\\" + fname).mkdir();
String filePath1 = filepath + filename;
System.out.println("Batch file running is " + filePath1);
Process p = Runtime.getRuntime().exec(new String[] { "cmd.exe", "/c", filePath1 });
p.getOutputStream().close();
p.waitFor();
} catch (Exception e) {
e.printStackTrace();
}
}
}
EDIT2: I have added the run for ConvertTO CSV. My code is doing say 10 things, and 9 of them are working fine except running two batch files with different names from the same folder
public class ConvertToCSV implements Runnable{
String fpath,utility_path,filename,fname,bat_file_path,tpath,csv_file_path,pg_db_url,pg_db,pg_db_uid,pg_db_pwd,plpgsql_path,Log_Path;
SimpleDateFormat sdf = new SimpleDateFormat("dd_mm_yy_hh_mm_ss");
Calendar cal = Calendar.getInstance();
#Override
public void run() {
try {
runConvertToCSV(fpath,utility_path,filename,fname,bat_file_path,tpath,csv_file_path,plpgsql_path);
} catch (Exception e) {
e.printStackTrace();
}
}
private void runConvertToCSV(String fpath,String utility_path,String filename,String fname,String bat_file,String tpath,String csv_file_path,String plpgsql_path) throws Exception{try{
String batch_content = "echo off \n "
+ "powershell.exe -file "
+ path_to_powershell_script_to_convert_excel_into_csv + "convertCSVSwiss.ps1 " + path_and_name_to_the_excel_file " -executionpolicy Unrestricted \n ";
String batch_name = "batch_" + excel_file_name +"_"+sdf.format(cal.getTime())+ ".bat";
Utils.createBatchFile(batch_content, bat_file_path, batch_name);
Utils.RunBatch(bat_file_path, batch_name,csv_file_path,fname);
}
catch (Exception e) {
e.printStackTrace();
}
}
EDIT3#:
My guess was that maybe because all the batch files are trying to access the same powershell script, that is why it is not working. But then i created ps script for every batch file. Also, added error stream to the stdout to check if there is any error and this is what i am getting:
Standard Error:
The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)
At C:\ER\ETL\ETL_SOURCE\convertCSVSwiss_Swiss_Sample_Data.ps1:24 char:2
+ $Worksheet.SaveAs($ExtractedFileName,6)
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : OperationStopped: (:) [], COMException
+ FullyQualifiedErrorId : System.Runtime.InteropServices.COMException
there are number of same error at different line. NOTE: It is the same ps script for all the batch files, it runs only for one and not for others. and that one can be anyone(no pattern).
If i run the above batch file manually, then it succeeds.

How to execute a java program from another java program in eclipse

I'm trying to run a java program, called Test.java from another java program Demo.java. Both programs are in the same package, I'm doing something like this:
try{
System.out.println("Executing another client");
runProcess("javac -cp gridgain-examples C:/Users/Desktop/gridgain/examples/src/main/java/apache/ignite/schemas/Test.java");
System.out.println("******");
runProcess("java -cp gridgain-examples C:/Users/Desktop/gridgain/examples/src/main/java/apache/ignite/schemas/Test.java");
} catch(Exception e) {
e.printStackTrace();
}
And the runProcess and printlines methods are:
private static void printLines(String cmd, InputStream ins) throws Exception {
String line = null;
BufferedReader in = new BufferedReader(
new InputStreamReader(ins));
while ((line = in.readLine()) != null) {
System.out.println(cmd + " " + line);
}
}
private static void runProcess(String command) throws Exception {
Process pro = Runtime.getRuntime().exec(command);
printLines(command + " stdout:", pro.getInputStream());
printLines(command + " stderr:", pro.getErrorStream());
pro.waitFor();
System.out.println(command + " exitValue() " + pro.exitValue());
}
But it's not executing. Please tell me how to do it?
Have you tried "C:\Users\Desktop\gridgain\examples\src\main\java\apache\ignite\schemas\Test.java"?
I'd comment this but don't have the reputation :(

Running Java Program in another Program gives error

I want to execute another Java program in my program. I have taken reference from here. For testing I have pasted same code as accepted answer shows.I have passed a simple HelloWorld program. Program compiles perfectly but gives Main class not found error.
Here is my code:
Server.java
public static void main(String args[]) {
try {
runProcess("javac D:\\HelloWorld.java");
runProcess("java D:\\HelloWorld");
} catch (Exception e) {
e.printStackTrace();
}
}
private static void printLines(String name, InputStream ins) throws Exception {
String line = null;
BufferedReader in = new BufferedReader(
new InputStreamReader(ins));
while ((line = in.readLine()) != null) {
System.out.println(name + " " + line);
}
}
private static void runProcess(String command) throws Exception {
Process pro = Runtime.getRuntime().exec(command);
printLines(command + " stdout:", pro.getInputStream());
printLines(command + " stderr:", pro.getErrorStream());
pro.waitFor();
System.out.println(command + " exitValue() " + pro.exitValue());
}
HelloWorld.java:
`public static void main(String args[]){
System.out.println("Hello World!");
}`
Output:
exitValue() 0 for javac
stderr: Error: Could not find or load main class D:\HelloWorld
exitValue() 1 for java
Compiling and running same program on CMD or IDE gives perfect output.
You want to start main from HelloWorld class? I think, in that case you should run program something like this:
java -cp 'D:\' HelloWorld
So, you need to specify ClassPath - 'D:\' and entry class name from classpath - HelloWorld.
Why try to do things the hard way? Use the inline compiler API and then simply execute the main() method on your new class after loading the class itself into your root classloader.

Running Background java program

I am trying to make a java application which runs another java program at certain point of event occurrence . As I have to run this process in background I am using & symbol . This is part of the application .
private static void printLines(String name, InputStream ins) throws Exception {
String line = null;
BufferedReader in = new BufferedReader(new InputStreamReader(ins));
while ((line = in.readLine()) != null) {
System.out.println(name + " " + line);
}
}
private static void runProcess(String command) throws Exception {
Process pro = Runtime.getRuntime().exec(command);
printLines(command + " stdout:", pro.getInputStream());
printLines(command + " stderr:", pro.getErrorStream());
// pro.waitFor();
System.out.println(command + " exitValue() " + pro.exitValue());
}
runProcess("javac test2.java");
runProcess("java test2 "+id+" "+pass+" "+choice+" &");//Id,pass,choice are arguments of java program
The problem I am facing is If I am print the lines os that program my actual application does not move to next part until my background process is over which takes long time and if I omit these output lines then the background process exits and gives this error :
java.lang.IllegalThreadStateException: process hasn't exited
And If I use pro.waitFor(); then again the first problem .What should I do?

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