RFR: 8175079: Lazy initialization of ImageReader breaks rmid

[Claes Redestad]

Done!

On 02/16/2017 05:27 PM, Alan Bateman wrote:
> I think go with the first for now.
>
> -Alan
>
>
> On 16/02/2017 16:24, Claes Redestad wrote:
>
>> Hi,
>>
>> please review this simple backout of a startup optimization that has 
>> proven to destabilize things like rmid. Patch inline..
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8175079
>>
>> diff -r 87f2a6fb4b9a src/java.base/share/classes/java/lang/System.java
>> --- a/src/java.base/share/classes/java/lang/System.java    Wed Feb 15 
>> 15:57:18 2017 +0100
>> +++ b/src/java.base/share/classes/java/lang/System.java    Thu Feb 16 
>> 17:18:49 2017 +0100
>> @@ -1945,9 +1945,6 @@
>>          // set security manager
>>          String cn = System.getProperty("java.security.manager");
>>          if (cn != null) {
>> -            // ensure image reader for java.base is initialized 
>> before security manager
>> -            Object.class.getResource("module-info.class");
>> -
>>              if (cn.isEmpty() || "default".equals(cn)) {
>>                  System.setSecurityManager(new SecurityManager());
>>              } else {
>> diff -r 87f2a6fb4b9a 
>> src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java
>> --- 
>> a/src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java 
>> Wed Feb 15 15:57:18 2017 +0100
>> +++ 
>> b/src/java.base/share/classes/jdk/internal/module/ModuleBootstrap.java 
>> Thu Feb 16 17:18:49 2017 +0100
>> @@ -115,12 +115,7 @@
>>          long t0 = System.nanoTime();
>>
>>          // system modules (may be patched)
>> -        ModuleFinder systemModules;
>> -        if (SystemModules.MODULE_NAMES.length > 0) {
>> -            systemModules = SystemModuleFinder.getInstance();
>> -        } else {
>> -            systemModules = ModuleFinder.ofSystem();
>> -        }
>> +        ModuleFinder systemModules = ModuleFinder.ofSystem();
>>
>>          PerfCounters.systemModulesTime.addElapsedTimeFrom(t0);
>>
>>
>> An alternative patch is to move the force initialization of the image 
>> reader from initPhase3 to SecurityManager,
>> which ensures it's initialized before a security manager is 
>> installed. This preserves the startup optimization in
>> case a SM is not installed:
>>
>> diff -r 87f2a6fb4b9a 
>> src/java.base/share/classes/java/lang/SecurityManager.java
>> --- a/src/java.base/share/classes/java/lang/SecurityManager.java Wed 
>> Feb 15 15:57:18 2017 +0100
>> +++ b/src/java.base/share/classes/java/lang/SecurityManager.java Thu 
>> Feb 16 17:23:57 2017 +0100
>> @@ -233,6 +233,11 @@
>>  public
>>  class SecurityManager {
>>
>> +    static {
>> +        // ensure image reader for java.base is initialized before 
>> security
>> +        // manager is installed
>> +        Object.class.getResource("module-info.class");
>> +    }
>>      /**
>>       * This field is <code>true</code> if there is a security check in
>>       * progress; <code>false</code> otherwise.
>>
>>
>> Thanks!
>>
>> /Claes
>