Out of memory exception on java with linux-redhat

Question

I am facing Outof memory issue on linux/redhat, and same program works on my windows machine.

My linux machine configuration is 15Gb RAM.

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.sql.ResultSet;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;

/**
 *
 * @author ndoshi
 */
public class Dwnld {

    BufferedImage bi8 = null, bi16 = null;
    ImageIcon ii = null;
    ResultSet rs, rsDwnld;
    String OG = "ogImage\\";
    String CROP8 = "Crop8\\";
    String CROP16 = "Crop16\\";
    String TIME = "", ErrorLog = "", ErrorLogPro = "";
    int hashInc8 = 0;
    int hashInc16 = 0;
    int totalround = 0;
    int countProcess = 0;
    boolean download_new = false;
    private int row = 0;
    int Dwnld = 0, NotDwnld = 0;
    final String OP_Log = "Log", OP_Error = "ErrorLog", OP_ErrorPro = "ErrorLogProcess";

    int r, g, b, k, ih, j;
    int sr = 0, sg = 0, sb = 0, sk = 0;
    int rg, gg, bg, kg;
    String s = "", s1 = "", hash16, hash8;

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new Dwnld();
    }

    public Dwnld(){
    try {
            BufferedImage image = null;
            InputStream is = null;
            OutputStream os = null;
            URL url = new URL("https://rukminim1.flixcart.com/image/312/312/t-shirt/u/g/k/33solidblackmelangeblack-sayitloud-m-original-imaehfytzzzazfyf.jpeg?q=70");
            is = url.openStream();
            os = new FileOutputStream(OG + "1.jpg");
            byte[] b = new byte[2048];
            int length;
            while ((length = is.read(b)) != -1) {
                os.write(b, 0, length);
            }
            image = ImageIO.read(new File(OG + "1.jpg"));
            is.close();
            os.close();
            System.out.println("Hash 16 = "+hash16);
            System.out.println("Hash 8 = "+hash8);
        } catch (Exception ex) {
            System.out.println(ex.getMessage());
        }

    }

}

I am running the sam eby increasing the memory with XMS & XMX as

java -Xms2048m -Xmx6096m Dwnld 

Error am getting :

Exception in thread "main" java.lang.OutOfMemoryError: unable to create new native thread
        at java.lang.Thread.start0(Native Method)
        at java.lang.Thread.start(Thread.java:714)
        at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1056)
        at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1332)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1359)
        at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1343)
        at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:563)
        at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301)
        at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
        at java.net.URL.openStream(URL.java:1037)
        at Dwnld.<init>(Dwnld.java:53)
        at Dwnld.main(Dwnld.java:43)

Answer 1

To start-with get thread dump and try to analyse it.

Alternatively there are many other ways that can act as workaround:

1. The /proc/sys/kernel/threads-max file provides a system-wide limit for the number of threads. The root user can change that value if they wish to:

   $ echo 100000 > /proc/sys/kernel/threads-max

2. In case of linux Threads are just processes with a shared address space and hence you should Check number of processes per user.

3. Check thread PID limit, as there is max PID limit based on value of kernel.pid_max limit parameter. Make use of this command $ sysctl -a | grep kernel.pid_max command $ sysctl -a | grep kernel.pid_max to get max allowable PID.
4. if you are not able to modify the OS settings is reducing the stack size. with something like JAVA_OPTS="-Xss256k"