./java -jar /Samplejavaprogram/Sample.jar

no main manifest attribute, in /Samplejavaprogram/Sample.jar

package org.myorg;

import java.io.*;
import java.util.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.logging.Level;
import java.util.*;

public class Sample {
    public static void main (String[] args) throws IOException  {
                    int CountComputers;
            FileInputStream fstream = new FileInputStream(
                    "/export/hadoop-1.0.1/bin/countcomputers.txt");
            DataInputStream input = new DataInputStream(fstream);
            BufferedReader br = new BufferedReader(new InputStreamReader(input));
            String result=br.readLine();
            CountComputers=Integer.parseInt(result);
            input.close();
            fstream.close();
            Connection con = null;
            Statement st = null;
                ResultSet rs = null;
               String url = "jdbc:postgresql://192.168.1.8:5432/NexentaSearch";
                String user = "postgres";
                String password = "valter89";
            ArrayList<String> paths = new ArrayList<String>();
            try
            {
                con = DriverManager.getConnection(url, user, password);
                        st = con.createStatement();
                        rs = st.executeQuery("select path from tasks order by id");
                while (rs.next()) { paths.add(rs.getString(1)); };
                PrintWriter zzz = null;
                    try
                    {
                            zzz = new PrintWriter(new FileOutputStream("/export/hadoop-1.0.1/bin/readwaysfromdatabase.txt"));
                    }
                    catch(FileNotFoundException e)
                    {
                            System.out.println("Error");
                            System.exit(0);
                    }
                    for (int i=0; i<paths.size(); i++)
                {
                    zzz.println("paths[i]=" + paths.get(i) + "n");
                    }
                    zzz.close();

            }
            catch (SQLException e)
            {
                System.out.println("Connection Failed! Check output console");
                e.printStackTrace();
            }
        }
}

group 'MyApplication'
version '1.0-SNAPSHOT'

apply plugin: 'java'
apply plugin: 'application'

sourceCompatibility = 1.8
targetCompatibility = 1.8

mainClassName ="com.common.Application"

buildscript {
    repositories {
        mavenCentral()
    }
}

repositories {
    mavenCentral()
}

// Include dependent libraries in archive.
jar {
    manifest {
        attributes "Main-Class": "$mainClassName"
    }

    from {
        configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
    }
}

dependencies {
    testCompile group: 'junit', name: 'junit', version: '4.12'
    //JSON
    compile group: 'org.json', name: 'json', version: '20090211'

    //Log4j
    compile group: 'log4j', name: 'log4j', version: '1.2.16'
}