How to get rid off java.lang.OutOfMemoryError: Java heap space

Question

I have went through many links and similar questions related to java.lang.OutOfMemoryError: Java heap space but none of the solutions resolved my problem. So here is my question, I have a web application where user uploads a Excel file that has records around 2500 my application reads contents of this file and inserts them into Database. but after inserting 700 records I am getting exception as throwable object caught= java.lang.OutOfMemoryError: Java heap space

Same code works if file contains 500 or less than 500 records. following is my JAVA_OPTS & CATALINA_OPTS variable in catalina.bat file

    JAVA_OPTS=-Xmx1536m -XX:MaxPermSize=128m
    CATALINA_OPTS=-Xms512m -Xmx512m

can anyone please tell me what can be done to resolve this issue?

chek out [http://stackoverflow.com/questions/3443937/java-heap-memory-error](http://stackoverflow.com/questions/3443937/java-heap-memory-error) — Madhusudan Joshi, May 23 '13 at 09:09
Definetly you have to rethink about performed operations. Don't try to read all ~2500 records in a one step. Make this process iterative. I mean, read portion of data, insert it into your db. Repeat this process until you reach the end. — Eugene, May 23 '13 at 09:13

score 0 · Answer 1 · answered May 23 '13 at 09:09

Probably you are loading the entire file in memory. Can you try to convert your Excel file to plain-text CSV and then read it line by line by using the Java class Scanner?

Scanner scanner = new Scanner("yourCsvFile.csv");

while (scanner.hasNextLine()) {
    String line = scanner.nextLine();

    //process your line
}

score 0 · Answer 2 · edited May 23 '17 at 12:18

can anyone please tell me what can be done to resolve this issue?

It sounds to me like you have a memory leak (i.e. a bug) in your application. Without seeing your code, we can't tell you where it is. However the answers to these questions explain how to find memory leaks in Java programs:

I should point out that you have specified two different values for the heap size in the JAVA_OPTS and CATALINA_OPTS variables. Only one of this is going to take effect, but which one depends on the details of the script that is used to start Tomcat.

However, a properly written application shouldn't run out of memory while uploading data from a spreadsheet. A heap size of 512Mb should be plenty.

thanks for your answer,can you tell me what changes should I make in order to make heap size 512Mb? because my tomcat manager always shows Max memory: 247.50 MB for JVM — Pranjali, May 23 '13 at 09:20

score 0 · Answer 3 · answered May 23 '13 at 09:14

You are probably using Hibernate to insert the records. Hibernate maintains a session cache of all saved objects and postpones any actual inserts until transaction commit. You must flush the session cache every 100 records or so. It is also advised to disable the second-level cache while doing a massive insert.

There are several other issues related to batch inserts with Hibernate and the official documentation is mandatory reading for anyone implementing it.

score 0 · Answer 4 · answered May 23 '13 at 09:17

0

Did you close you File stream?If you didn't close you file stream,the heap size would be very bigger!Then it would throw a OutOfMemoryError exception.So,check that if you close the file stream!

answered May 23 '13 at 09:17

Rhain

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How to get rid off java.lang.OutOfMemoryError: Java heap space

4 Answers4