FULL PRODUCT VERSION :
java version "1.6.0_22"
Java(TM) SE Runtime Environment (build 1.6.0_22-b04)
Java HotSpot(TM) Client VM (build 17.1-b03, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
PKCS11 driver has limit for session count.

A DESCRIPTION OF THE PROBLEM :
After refactoring done in 1.6.0_21 in sun.security.pkcs11.SessionManager it is not possible to initialize SunPKCS11  provider more times than PKCS11 driver maxSessionCount limit. When initializing (maxLimitCount + 1) instance exception is thrown.

In 1.6.0_20 or earlier this works fine.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create in loop more than maxSessionCount (this is specific for PKCS11 driver).  In maxSessionCounty + 1 loop exception is thrown.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
no exception is thrown
ACTUAL -

Exception in thread "main" java.security.ProviderException: Initialization failed
	at sun.security.pkcs11.SunPKCS11.<init>(SunPKCS11.java:340)
	at sun.security.pkcs11.SunPKCS11.<init>(SunPKCS11.java:90)
	at pl.unizeto.procertum.pkcs11.SunPkcs11BugTest.main(SunPkcs11BugTest.java:29)
Caused by: java.security.ProviderException: Could not obtain session
	at sun.security.pkcs11.SessionManager.getOpSession(SessionManager.java:134)
	at sun.security.pkcs11.Token.<init>(Token.java:118)
	at sun.security.pkcs11.SunPKCS11.initToken(SunPKCS11.java:780)
	at sun.security.pkcs11.SunPKCS11.<init>(SunPKCS11.java:331)

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
        // Maximum session count supported by pkcs11 driver.
        // If you don't know what is the limit for your driver set it to 1000
        // or higher value.
        // If driver has no limit for session count this test works fine.
        int driverMaxSessions = 32;
        
        StringBuilder pkcs11Cfg = new StringBuilder();
        pkcs11Cfg.append("name = PKCS11\n");
        pkcs11Cfg.append("library = crypto3PKCS.dll");
        
        for(int i=0; i < driverMaxSessions + 1; i++) {
        
            InputStream config = new ByteArrayInputStream(pkcs11Cfg.toString().getBytes());
            
            // fails with "java.security.ProviderException: Could not obtain session"
            // when in (driverMaxSession + 1) loop on JRE 6u20 or later
            SunPKCS11 provider = new sun.security.pkcs11.SunPKCS11(config);
            provider.logout();
        }
---------- END SOURCE ----------