JVM File Descriptors Test

This test reports useful statistics pertaining to file descriptors.


This test will work only if the target Java application uses the JDK/JRE offered by one of the following vendors only: Oracle, Sun, OpenJDK. IBM JDK/JRE is not supported.

Target of the test : A Java application

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the Java application being monitored

Configurable parameters for the test
Parameter Description

Test period

How often should the test be executed.


The host for which the test is to be configured.


The port number at which the specified host listens to.

Metric Collection Type

This test can extract metrics from the Java application using either of the following mechanisms:

  • Using the eg_btm.jar file available in the <eG_INSTALL_DIR>\lib\apm\java\default folder;
  • Using SNMP-based access to the Java runtime MIB statistics;
  • By contacting the Java runtime (JRE) of the application via JMX

To configure the test to collect metrics from the eg_btm.jar file, select the JAR option. On the other hand, to configure the test to use SNMP or JMX options, choose the Others option. By default, JAR option is chosen here.

JMX Remote Port

This parameter appears only if the Metric Collection Type flag is set to JMX. Here, specify the port at which the JMX listens for requests from remote hosts. Ensure that you specify the same port that you configured in the management.properties file in the <JAVA_HOME>\jre\lib\management folder used by the target application . To know more, refer to Enabling JMX Support for JREtopic.


This parameter appears only if the mode is set to JMX. The JNDIname is a lookup name for connecting to the JMX connector. By default, this is jmxrmi. If you have resgistered the JMX connector in the RMI registery using a different lookup name, then you can change this default value to reflect the same. 

JMX User, JMX Password, and Confirm password

These parameters appear only if the Mode is set to JMX. If JMX requires authentication only (but no security), then ensure that the user and password parameters are configured with the credentials of a user with read-write access to JMX. To know how to create this user, refer to Configuring the eG Agent to Support JMX Authentication. Confirm the password by retyping it in the Confirm Password text box.


This parameter appears only if the Mode is set to JMX. This test uses a JMX Provider to access the MBean attributes of the target Java application and collect metrics. Specify the package name of this JMX Provider here. By default, this is set to com.sun.jmx.remote.protocol.


Specify the duration (in seconds) for which this test should wait for a response from the target Java application. If there is no response from the target beyond the configured duration, the test will timeout. By default, this is set to 240 seconds if the Mode is JMX, and 10 seconds if the Mode is SNMP.

JMX Registry SSL

This parameter appears only if the Mode is set to JMX. If you have registered the JMX connector in an SSL-enabled RMI registry , set this flag to Yes. By default, this is set to No.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Open file descriptors in JVM

Indicates the number of file descriptors currently open for the application.



Maximum file descriptors in JVM

Indicates the maximum number of file descriptors allowed for the application.



File descriptor usage by JVM

Indicates the file descriptor usage in percentage.