Byteman Best Practical 1 - (parameter value, AT INVOKE)

hat I want to know :

    According to log,  NPE happen when getDeploymentTimeStamp method is called, so I would like to know what value is null and what is going on there.

ErrorMsg :  

             java.lang.NullPointerException

18:04:54,160 ERROR [org.jboss.as.server.deployment.scanner] (DeploymentScanner-threads - 1) JBAS015016: Initial deployment scan failed: java.lang.NullPointerException     at org.jboss.as.server.deployment.scanner.FileSystemDeploymentService.getDeploymentTimestamp     (FileSystemDeploymentService.java:723) [jboss-as-deployment-scanner-7.3.4.Final-redhat-1.jar:7.3.4.Final-redhat-1]     ............

Test Source :

•       org.jboss.as.server.deployment.scanner.FileSystemDeploymentService

 

private long getDeploymentTimestamp(File deploymentFile) {      if (deploymentFile.isDirectory()) {              // Scan for most recent file              long latest = deploymentFile.lastModified();              for (File child : deploymentFile.listFiles()) {                  long childTimestamp = getDeploymentTimestamp(child);                  if (childTimestamp > latest) {                      latest = childTimestamp;                  }              }              return latest;          } else {              return deploymentFile.lastModified();          }      }

Byteman script :

RULE Test autodeployment checking all files under the exploded folder CLASS org.jboss.as.server.deployment.scanner.FileSystemDeploymentService METHOD getDeploymentTimestamp AT INVOKE  getDeploymentTimestamp BIND subfile = $child; IF TRUE DO    System.out.println("=========================JHOUSE-debug=================");    System.out.println("deploymentFile : " +  $1);    System.out.println("subFile : " + subfile); ENDRULE

Result :

INFO  [stdout] (DeploymentScanner-threads - 1) Rule.execute called for Test autodeployment_2 INFO  [stdout] (DeploymentScanner-threads - 1) HelperManager.install for helper class org.jboss.byteman.rule.helper.Helper INFO  [stdout] (DeploymentScanner-threads - 1) calling activated() for helper class org.jboss.byteman.rule.helper.Helper INFO  [stdout] (DeploymentScanner-threads - 1) Default helper activated INFO  [stdout] (DeploymentScanner-threads - 1) calling installed(Test autodeployment) for helper classorg.jboss.byteman.rule.helper.Helper  INFO  [stdout] (DeploymentScanner-threads - 1) Installed rule using default helper : Test autodeployment  INFO  [stdout] (DeploymentScanner-threads - 1) Test autodeployment execute  INFO  [stdout] (DeploymentScanner-threads - 1) =========================JHOUSE-debug================= INFO  [stdout] (DeploymentScanner-threads - 1) deploymentFile : /home/jooho/Applications/JBoss/EAP/jboss-eap-6.2.4/standalone/deployments/cluster.war INFO  [stdout] (DeploymentScanner-threads - 1) subFile : /home/jooho/Applications/JBoss/EAP/jboss-eap-6.2.4/standalone/deployments/cluster.war/index.jsp

Compared between source and by teman script, you can easily map each value that related with each other.

If you have any questions, please leave comment.