IOException on Solaris, as .audit files are not getting closed

[srrprasad]

On Solaris 10 with Weblogic 12c and audit4j 2.3.1, when load tests are run, we are seeing IOException due to too many open files.
java.io.FileNotFoundException: /audit/Audit_Log-2016-12-14.audit (Too many open files)
at java.io.RandomAccessFile.open0(Native Method)
at java.io.RandomAccessFile.open(RandomAccessFile.java:316)
at java.io.RandomAccessFile.(RandomAccessFile.java:243)
at java.io.RandomAccessFile.(RandomAccessFile.java:124)
at org.audit4j.core.handler.file.ZeroCopyFileWriter.write(ZeroCopyFileWriter.java:88)

When looked at the open files using pfiles -F command, we are seeing many .audit files in open mode as below:
pfiles -F | grep -i audit
.... removed audit jar files ...
/audit/Audit_Log-2016-12-15.audit
/audit/Audit_Log-2016-12-15.audit
This makes the number of open files grow very quickly to more than the allowed 65k files, causing the error.
Our code is very simple:
private static AuditManager manager = AuditManager.getInstance();
//create builder with data
manager.audit(builder.build());