We have actually increase the memory for the jvm to 256M and now the old generation looks very small but the Perm Generation is quite high nearly 80%. Sample data capture via jstat is as below. What does a high perm generation indicate here?
Timestamp S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT
173656.0 1152.0 1216.0 864.0 0.0 84928.0 26778.0 174784.0 11967.6 21248.0 17057.8 62 3.653 0 0.000 3.653
173671.0 1152.0 1216.0 864.0 0.0 84928.0 27843.4 174784.0 11967.6 21248.0 17057.8 62 3.653 0 0.000 3.653
173686.1 1152.0 1216.0 864.0 0.0 84928.0 27843.4 174784.0 11967.6 21248.0 17057.8 62 3.653 0 0.000 3.653
173701.1 1152.0 1216.0 864.0 0.0 84928.0 27843.4 174784.0 11967.6 21248.0 17057.8 62 3.653 0 0.000 3.653
173716.0 1152.0 1216.0 864.0 0.0 84928.0 27843.4 174784.0 11967.6 21248.0 17057.8 62 3.653 0 0.000 3.653
Samples before restart
Timestamp S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT
261578.8 0.00 16.89 68.70 8.89 80.74 45 2.551 0 0.000 2.551
261593.8 0.00 16.89 70.97 8.89 80.74 45 2.551 0 0.000 2.551
261608.8 0.00 16.89 72.49 8.89 80.74 45 2.551 0 0.000 2.551
261623.8 0.00 16.89 75.00 8.89 80.74 45 2.551 0 0.000 2.551
261638.8 0.00 16.89 77.76 8.89 80.74 45 2.551 0 0.000 2.551
261653.8 0.00 16.89 80.77 8.89 80.74 45 2.551 0 0.000 2.551
261668.8 0.00 16.89 83.03 8.89 80.74 45 2.551 0 0.000 2.551
261683.8 0.00 16.89 85.29 8.89 80.74 45 2.551 0 0.000 2.551
261698.8 0.00 16.89 87.57 8.89 80.74 45 2.551 0 0.000 2.551
261713.8 0.00 16.89 90.57 8.89 80.74 45 2.551 0 0.000 2.551
261728.8 0.00 16.89 93.35 8.89 80.74 45 2.551 0 0.000 2.551
261743.8 0.00 16.89 95.61 8.89 80.74 45 2.551 0 0.000 2.551
261758.8 0.00 16.89 98.61 8.89 80.74 45 2.551 0 0.000 2.551
261773.8 20.83 0.00 1.36 8.95 80.74 46 2.685 0 0.000 2.685
261788.8 20.83 0.00 4.66 8.95 80.74 46 2.685 0 0.000 2.685
261803.8 20.83 0.00 6.88 8.95 80.74 46 2.685 0 0.000 2.685
261818.8 20.83 0.00 9.67 8.95 80.74 46 2.685 0 0.000 2.685
261833.8 20.83 0.00 10.78 8.95 80.74 46 2.685 0 0.000 2.685
261848.8 20.83 0.00 13.56 8.95 80.74 46 2.685 0 0.000 2.685
261863.9 20.83 0.00 15.78 8.95 80.74 46 2.685 0 0.000 2.685
261878.8 20.83 0.00 19.32 8.95 80.74 46 2.685 0 0.000 2.685
261893.8 20.83 0.00 21.55 8.95 80.74 46 2.685 0 0.000 2.685
261908.8 20.83 0.00 24.33 8.95 80.74 46 2.685 0 0.000 2.685
261923.8 20.83 0.00 27.11 8.95 80.74 46 2.685 0 0.000 2.685
261938.8 20.83 0.00 29.84 8.95 80.74 46 2.685 0 0.000 2.685
261953.8 20.83 0.00 32.06 8.95 80.74 46 2.685 0 0.000 2.685
261968.8 20.83 0.00 34.85 8.95 80.74 46 2.685 0 0.000 2.685
261983.8 20.83 0.00 38.89 8.95 80.74 46 2.685 0 0.000 2.685
Samples afte restart
Timestamp S0C S1C S0U S1U EC EU OC OU PC PU YGC YGCT FGC FGCT GCT
135.8 0.00 0.00 72.71 0.00 70.88 0 0.000 0 0.000 0.000
150.8 0.00 0.00 76.71 0.00 70.91 0 0.000 0 0.000 0.000
165.8 0.00 0.00 78.71 0.00 70.94 0 0.000 0 0.000 0.000
180.7 0.00 0.00 82.71 0.00 72.79 0 0.000 0 0.000 0.000
195.8 0.00 0.00 84.71 0.00 72.81 0 0.000 0 0.000 0.000
210.8 0.00 0.00 88.71 0.00 72.90 0 0.000 0 0.000 0.000
225.8 0.00 0.00 92.71 0.00 72.93 0 0.000 0 0.000 0.000
240.8 0.00 0.00 94.71 0.00 72.95 0 0.000 0 0.000 0.000
255.8 0.00 0.00 100.00 0.00 73.02 0 0.000 0 0.000 0.000
270.8 0.00 78.72 6.68 0.00 73.49 1 0.286 0 0.000 0.286
285.8 0.00 78.72 10.66 0.00 73.50 1 0.286 0 0.000 0.286
300.8 0.00 78.72 14.32 0.00 73.54 1 0.286 0 0.000 0.286
315.8 0.00 78.72 18.89 0.00 73.57 1 0.286 0 0.000 0.286
330.8 0.00 78.72 24.85 0.00 73.57 1 0.286 0 0.000 0.286
345.8 0.00 78.72 30.18 0.00 76.84 1 0.286 0 0.000 0.286
360.8 0.00 78.72 32.82 0.00 76.86 1 0.286 0 0.000 0.286
375.8 0.00 78.72 36.04 0.00 76.87 1 0.286 0 0.000 0.286
390.8 0.00 78.72 40.00 0.00 76.89 1 0.286 0 0.000 0.286
405.8 0.00 78.72 43.96 0.00 76.91 1 0.286 0 0.000 0.286
420.8 0.00 78.72 46.61 0.00 76.92 1 0.286 0 0.000 0.286
435.8 0.00 78.72 47.63 0.00 76.92 1 0.286 0 0.000 0.286
450.8 0.00 78.72 47.63 0.00 76.92 1 0.286 0 0.000 0.286
465.8 0.00 78.72 47.63 0.00 76.92 1 0.286 0 0.000 0.286
480.8 0.00 78.72 47.63 0.00 76.92 1 0.286 0 0.000 0.286
495.8 0.00 78.72 48.54 0.00 76.93 1 0.286 0 0.000 0.286
510.8 0.00 78.72 48.54 0.00 76.93 1 0.286 0 0.000 0.286
525.8 0.00 78.72 48.54 0.00 76.93 1 0.286 0 0.000 0.286
540.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
555.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
570.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
585.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
600.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
615.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
630.8 0.00 78.72 49.11 0.00 76.93 1 0.286 0 0.000 0.286
645.8 0.00 78.72 49.98 0.00 76.93 1 0.286 0 0.000 0.286
660.8 0.00 78.72 49.98 0.00 76.93 1 0.286 0 0.000 0.286
675.8 0.00 78.72 49.98 0.00 76.93 1 0.286 0 0.000 0.286
690.8 0.00 78.72 49.98 0.00 76.93 1 0.286 0 0.000 0.286
705.8 0.00 78.72 49.98 0.00 76.93 1 0.286 0 0.000 0.286
720.8 0.00 78.72 50.55 0.00 76.93 1 0.286 0 0.000 0.286
735.8 0.00 78.72 51.12 0.00 76.93 1 0.286 0 0.000 0.286
750.8 0.00 78.72 51.12 0.00 76.93 1 0.286 0 0.000 0.286
765.8 0.00 78.72 51.12 0.00 76.93 1 0.286 0 0.000 0.286
780.8 0.00 78.72 51.12 0.00 76.93 1 0.286 0 0.000 0.286
795.8 0.00 78.72 51.12 0.00 76.93 1 0.286 0 0.000 0.286
810.8 0.00 78.72 51.12 0.00 76.93 1 0.286 0 0.000 0.286
825.8 0.00 78.72 51.69 0.00 76.93 1 0.286 0 0.000 0.286
840.8 0.00 78.72 51.69 0.00 76.93 1 0.286 0 0.000 0.286
855.8 0.00 78.72 51.69 0.00 76.93 1 0.286 0 0.000 0.286
870.8 0.00 78.72 51.69 0.00 76.93 1 0.286 0 0.000 0.286
885.8 0.00 78.72 52.26 0.00 76.95 1 0.286 0 0.000 0.286
900.8 0.00 78.72 52.26 0.00 76.95 1 0.286 0 0.000 0.286
915.8 0.00 78.72 53.12 0.00 76.95 1 0.286 0 0.000 0.286
930.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
945.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
960.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
975.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
990.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
1005.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
1020.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
1035.8 0.00 78.72 53.69 0.00 76.95 1 0.286 0 0.000 0.286
1050.8 0.00 78.72 54.27 0.00 76.95 1 0.286 0 0.000 0.286
1065.8 0.00 78.72 54.27 0.00 76.95 1 0.286 0 0.000 0.286
1080.8 0.00 78.72 54.27 0.00 76.95 1 0.286 0 0.000 0.286
1095.8 0.00 78.72 54.27 0.00 76.95 1 0.286 0 0.000 0.286
1110.8 0.00 78.72 55.12 0.00 76.97 1 0.286 0 0.000 0.286
1125.8 0.00 78.72 55.46 0.00 76.97 1 0.286 0 0.000 0.286
1140.8 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1155.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1170.8 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1185.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1200.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1215.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1230.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1245.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1260.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1275.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1290.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1305.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
1320.9 0.00 78.72 56.03 0.00 76.97 1 0.286 0 0.000 0.286
Classes used are
import java.io.*;
import java.net.*;
import java.util.*;
import java.util.Date;
import java.text.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.SQLException;
import java.sql.*;
import java.util.concurrent.LinkedBlockingQueue;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeMessage;
import com.jolbox.bonecp.BoneCP;
import com.jolbox.bonecp.BoneCPConfig;
Skeleton of the codes.
public static void main(String[] args) {
new sServer7888();
}
sServer7888() {
try{
final ServerSocket serverSocketConn = new ServerSocket(7888);
while (true){
try{
Socket socketConn1 = serverSocketConn.accept();
new Thread(new ConnectionHandler(socketConn1)).start();
}
catch(Exception e){
e.printStackTrace(System.out);
}
}
}
catch (Exception e) {
e.printStackTrace(System.out);
}
}
class ConnectionHandler implements Runnable {
private Socket receivedSocketConn1;
ConnectionHandler(Socket receivedSocketConn1) {
this.receivedSocketConn1=receivedSocketConn1;
}
public void run() {
while ((nextChar=readIn1.read()) != -1) {
completeMessage += (char) nextChar;
if (nextChar == '*')
{
//calling of various function depends on the input data
completeMessage="";
}
}
}
}
}
You app is just running - there is nothing special here.
If the application was running before (meaning that all classes were loaded) you don't have to worry about the PermGen space.
Otherwise it would be nice if you could show all your memory-related system parameters.
Concerning the 2nd and 3rd samples:
The 2nd sample (before restart) shows that the application has never run a FullGC. It means, that the space for objects is enough. Similarly technically no change in PermGen space, it means that the application already loaded all required classes, no new classloading happens.
The third example (after restart) shows that the application is slowly loading all necessary classes, at the end technically no new classes are loaded for minutes. It does not mean, that it will never happen, it only means that the app after 20 minutes already loaded the required classes. So, no new big increase is expected.
Although it may happen that some hidden part of the application becomes active, and you will load a number of classes, imagine that you have 5 times more space than you actually allocated. Also, it is a finite process, after a class was loaded, it will not be loaded again.