style(appsec): address PR review feedback on GlassFish multipart instrumentation

- Use try-with-resources for OutputStream in GlassFishBlockingHelper
- Cache Config limit values as static finals in GlassFishBlockingHelper
  to avoid per-request Config.get() calls (consistent with ParameterCollector)
- Remove Config import from GlassFishMultipartInstrumentation (now reads
  limits from GlassFishBlockingHelper static fields)
- Add comment to skipVersions explaining the jakarta namespace reason
- Add assertInverse to glassfish muzzle block for defensive CI coverage

Author: jandro996

dd-java-agent/instrumentation/tomcat/tomcat-appsec/tomcat-appsec-7.0/build.gradle

@@ -20,7 +20,8 @@ muzzle {
     group = 'org.glassfish.main.extras'
     module = 'glassfish-embedded-all'
     versions = '[4.0,]'
-    skipVersions += '6.1.0'
+    skipVersions += '6.1.0' // GlassFish 6.1.0+ uses jakarta.* namespace; our advice uses javax.servlet.http.Part
+    assertInverse = true
   }
 }
 

dd-java-agent/instrumentation/tomcat/tomcat-appsec/tomcat-appsec-7.0/src/main/java/datadog/trace/instrumentation/tomcat7/GlassFishBlockingHelper.java

@@ -1,6 +1,7 @@
 package datadog.trace.instrumentation.tomcat7;
 
 import datadog.appsec.api.blocking.BlockingContentType;
+import datadog.trace.api.Config;
 import datadog.trace.api.gateway.Flow;
 import datadog.trace.bootstrap.blocking.BlockingActionHelper;
 import java.io.OutputStream;
@@ -10,6 +11,9 @@
 
 public final class GlassFishBlockingHelper {
 
+  static final int MAX_FILE_CONTENT_COUNT = Config.get().getAppSecMaxFileContentCount();
+  static final int MAX_FILE_CONTENT_BYTES = Config.get().getAppSecMaxFileContentBytes();
+
   public static boolean commitBlocking(
       HttpServletRequest request,
       HttpServletResponse response,
@@ -34,9 +38,9 @@ public static boolean commitBlocking(
         if (body != null) {
           response.setHeader("Content-Type", BlockingActionHelper.getContentType(type));
           response.setHeader("Content-Length", Integer.toString(body.length));
-          OutputStream os = response.getOutputStream();
-          os.write(body);
-          os.close();
+          try (OutputStream os = response.getOutputStream()) {
+            os.write(body);
+          }
         }
       }
       response.flushBuffer();

dd-java-agent/instrumentation/tomcat/tomcat-appsec/tomcat-appsec-7.0/src/main/java/datadog/trace/instrumentation/tomcat7/GlassFishMultipartInstrumentation.java

@@ -9,7 +9,6 @@
 import datadog.appsec.api.blocking.BlockingException;
 import datadog.trace.agent.tooling.Instrumenter;
 import datadog.trace.agent.tooling.InstrumenterModule;
-import datadog.trace.api.Config;
 import datadog.trace.api.gateway.BlockResponseFunction;
 import datadog.trace.api.gateway.CallbackProvider;
 import datadog.trace.api.gateway.Flow;
@@ -127,8 +126,8 @@ static void after(
       } catch (Exception ignored) {
       }
 
-      int maxFiles = Config.get().getAppSecMaxFileContentCount();
-      int maxBytes = Config.get().getAppSecMaxFileContentBytes();
+      int maxFiles = GlassFishBlockingHelper.MAX_FILE_CONTENT_COUNT;
+      int maxBytes = GlassFishBlockingHelper.MAX_FILE_CONTENT_BYTES;
 
       List<String> filenames = null;
       List<String> contents = null;