Java Control Panel

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Java Control Panel

The Java Control Panel is a multipurpose control panel. It allows you to view and set a wide range of parameters controlling how, or if, Java technology runs on your computer. It lets you view and delete temporary files used by the Java Plug-in, which allows Java technology to be used by your Web browser to run applets; and Java Web Start, which allows you to run Java applications over the network. It allows you to control certificates, making it safe to run applets and applications over the network. It enables you to view an active deployment rule set, and to manage the exception site list. It allows you to set runtime parameters for applets that run with Java Plug-in and applications that run with Java Web Start. It provides a mechanism for updating your version of the Java platform so that you always have the latest Java Runtime Environment (JRE). And it allows you to set options for debugging, applet handling, etc. The Java Control Panel includes the following separately viewable panels:

Contents

• General
• Update
• Java
• Security
• Advanced

General

The General panel looks like this:

It includes three subpanels: About, NetworkSettings, and Temporary Internet Files. As of the JDK 7u10 release,this panel also informs you whether Java is enabled in the browser.This setting is contolled in the Security panel.

About

The About... button displaysversion information for the latest JRE installed on thecomputer.

NetworkSettings

These settings are for network connections. Press theNetwork Settings... button to get the NetworkSettings dialog. There are four choices:

Use browser settings

Check this to use the browser default proxy settings. This isthe default setting (checked).

Use proxy server

You have two choices here:

• You can set the Address and the Port for a proxy server withthe option to bypass it for local addresses.
• You can press the Advanced ... button to getthe Advanced Network Settings dialog. In this panel you canindividually set the proxy server for HTTP, Secure, FTP, and Socksconnections. You can also provide a list of addresses for which youdo not want to use a proxy server. The Advanced Network Settingspanel looks like this:

Use automatic proxy configuration script

You can specify the location (URL) for the JavaScript file (.jsor .pac extension) that contains the FindProxyForURLfunction. FindProxyForURL has the logic to determinethe proxy server to use for a connection request.

Direct Connection

Select this for situations where you do not want to use aproxy.

TemporaryInternet Files

You can do the following:

• Press the Settings... button to get theTemporary Files Settings dialog from which you can perform thefollowing:
  • Specify if you want to keep temporary files on yourcomputer.
  • Specify the location where temporary files are kept.
  • Specify the compression level for JAR files.
  • Specify the amount of disk space for storing temporaryfiles.
  • Delete temporary files by pressing the DeleteFiles... button, which displays the Delete Temporary Filesdialog. From this dialog, you can specify which files you want todelete:
    • Trace and Log Files
    • Cached Applications and Applets
    • Installed Applications and Applets
  • Restore default settings for the Temporary Files Settingsdialog by pressing the Restore Defaultsbutton.
• Press the View... button to get the Java CacheViewer dialog. This dialog enables you to list applications,resources, and deleted applications stored in the Java cache. Inaddition, you may perform the following:
  • Run and visit the Web page of applications.
  • View the JNLP file of applications and resources.

Update

On Microsoft Windows platforms, the Update panel looks like this:

The Update panel, in conjunction with the JavaUpdate Scheduler (jusched.exe), is used to provide thelatest Java updates to the end user.

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Note: This panel is only available on Microsoft Windows and Mac OS X and only for users with Administrative privileges. On Microsoft Windows, if both the 32-bit and 64-bit versions of Java are installed, this panel is not available. In this event, you have to launch the Java Control Panel directly from the 32-bit directory command line (C:\Program Files (x86)\Java\jre7\bin\javacpl.exe).

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Update Panel Options

There are two basic options on the Update tab:

• Automatic update: Available only on Microsoft Windows XP and higher, and set by default
• Manual update

Automatic update is performed on a scheduled basis and it isselected by checking the Check for Updates Automaticallycheck box.

Manual update is performed by pressing the Update Nowbutton.

If you select automatic update, you can then set thenotification via the Notify Me: drop-down menu, and you canset the update schedule via the Advanced... button.

With notification, you can chose to be notified before an updateis downloaded and before it is installed; or you can chose to benotified only before an update is installed (i.e., the download isautomatic).

The Advanced... allows you to select the desiredfrequency for updates: daily, weekly, or monthly (default). Fordaily updates, you can select the time of the day for the update. For weekly updates, you can select the day of the week and the timeof the day. For monthly updates, you can select the day of theweek and the time of the day. Monthly updates check weekly and notify you within 30 days that an update is available, however, if an update is considered critical you are notified within a week of its release.

You can do manual updates at any time by pressing the UpdateNow button. This allows you to do immediate, unscheduledupdates.

Java Update Scheduler

On Microsoft Windows platforms, the Java Update Scheduler (jusched.exe) is used forlaunching automatic updates when Update Automatically isselected in the Update tab. jusched.exe runs as abackground process that launches the Update Manager at predefinedintervals set by the user through the Advanced... button ofthe Update tab. The Update Manager coordinates the updateprocess.

jusched.exe is launched when the user reboots thecomputer after installing the SDK/JRE. It is normally transparentto the user but can be viewed in the Processes tab of the WindowsTask Manager. Should a user for some reason not want the schedulerto run, it can be killed via End Process button of theProcesses tab.

Java

The Java panel looks like this:

Click the View... button to accessthe Java Runtime Environment Settings dialog.

Java Runtime Environment Settings

These settings will be used when a Java applicationis launched. The Java Runtime Environment Settings dialog lookslike the following on Microsoft Windows:

Each row in the Java Runtime Versions panelrepresents a Java Runtime Environment that is installed in yourcomputer. You may modify the value in each cell by double-clickingit:

• Platform: The version of the Java RuntimeEnvironment
• Product: The full version number of the JavaRuntime Environment (which includes the update number)
• Location: The URL that Java Update Scheduleruses to launch automatic updates
• Path: The full path name of the Java RuntimeEnvironment
• Runtime Parameters: Optional custom optionsused to override the Java Plug-in default startup parameters
• Enabled: This option is for selecting which ofthe (older) JRE versions to consider when running an app using JavaPlug-in or Java Web Start. If this check box is not selected, thenJava Plug-in and Java Web Start will not use this JRE to launchJava apps. However, the current JRE might be used regardless ofthis checkbox. This checkbox does not affect stand aloneapplications, it is only for Java in the browser. Note that if allJava apps are disabled from running in the browser, by de-selecting Enable the Java content in the browser in the Security panel,enabling the JRE here has no effect.

Click the Find button to launch the JREFinder. This utility searches for unregistered privateJava Runtime Environments installed in your computer and adds themto the Java Runtime Versions panel.

Click the Add button to manually add a JavaRuntime Environment to the Java Runtime Versions panel. When youclick the Add button, a new row appears in theJava Runtime Versions panel; however, there are novalues for Platform, Product,Path, Runtime Parameters, andEnabled; you must specify them yourself.

Click the Remove button to remove the selectedJava Runtime Environment from the Java RuntimeVersions panel.

Notes

There will always be at least one entry. It will be the mostrecently installed JRE; i.e., the JRE associated with the JavaControl Panel.

Microsoft Windows will show all JREs installed on a computer.The Java Control Panel finds the JREs by looking in the registry.On Solaris, Linux, or Mac OS X, the situation is different.There is no registry so thereis no easy way to find the JREs that a user may have installed. TheJRE that Java Web Start or Java Plug-in is using to deployapplications is the JRE that is considered registered.Consequently, use the Find, Add,and Remove buttons to change which JREs are listedin the Java Runtime Environments panel. On Mac OS X, only the currently installed JRE is displayed, JDKs are not included.

For Solaris, Linux, or Mac OS X, only version 5.0 or higher should be added. ForMicrosoft Windows, where all JREs are found in the registry,version 1.3.1 or higher will be displayed.

Example:

Assume you are running on Microsoft Windows with MicrosoftInternet Explorer, have first installed version 1.4.2, then version5.0, and you want to run 1.4.2.

1. Go to the j2re1.4.2\bin directory where JRE 1.4.2was installed. On a Windows default installation, this would behere: C:\Program Files\Java\j2re1.4.2\bin
2. Double-click the jpicpl32.exe file located there.It will launch the control panel for 1.4.2.
3. Select the Browser tab. Microsoft Internet Explorer might stillappear to be set (checked). However, when 5.0 was installed, theregistration of the 1.4.2 JRE with Internet Explorer wasoverwritten by the 5.0 JRE.
4. If Microsoft Internet Explorer is shown as checked, uncheck itand click Apply. You will see a confirmation dialog stating thatbrowser settings have changed.
5. Check Microsoft Internet Explorer and click Apply. You shouldsee a confirmation dialog.
6. Restart the browser. It should now use the 1.4.2 JRE forconventional APPLET tags.

You can add a JRE by pressing Add and specifyingits location (see notes above).

For Windows and Solaris, Linux, or Mac OS X you can optionally set JavaRuntime Settings for the JRE.

Java Runtime Parameters

You can override the Java Plug-in default startup parameters byspecifying custom options in the Java Runtime Parameters field.With the exception of setting classpath andcp, the syntax is the same as used with parameters to thejava command line invocation. See the java launcherfor a full list of command line options:

java launcher: Windows, Solaris, Linux, or Mac OS X.

Below are some examples of Java runtime parameters.

Setting classpath andcp

The following format should be used for settingclasspath and cp in Java Plug-in. Itdiffers slightly from the java command line format,which uses a space instead of the equal (=) sign.

-classpath=-cp=

Enabling and disabling assertion support

To enable assertion support, the following system property mustbe specified in the Java Runtime Parameters:

-[ enableassertions | ea ][:'...' | : ]

To disable assertion in the Java Plug-in, specify the followingin the Java Runtime Parameters:

-[ disableassertions | da ][:'...' | : ]

Assertion is disabled in Java Plug-in code by default. Since theeffect of assertion is determined during Java Plug-in startup,changing assertion settings in the Java Plug-in Control Panel willrequire a browser restart in order for the new settings to takeeffect.

Because Java code in Java Plug-in also has built-in assertion,it is possible to enable the assertion in Java Plug-in code throughthe following:

-[ enableassertions | ea ]:sun.plugin

Tracing and logging support

Tracing is a facility to redirect any output in the Java Consoleto a trace file (.plugin.trace).

-Djavaplugin.trace=true-Djavaplugin.trace.option=basic|net|security|ext|liveconnect

If you do not want to use the default trace file name:

-Djavaplugin.trace.filename=

Similar to tracing, logging is a facility to redirect any outputin the Java Console to a log file(.plugin.log) using the Java LoggingAPI. Logging can be turned on by enabling the propertyjavaplugin.logging.

-Djavaplugin.logging=true

If you do not want to use the default log file name, enter:

-Djavaplugin.log.filename=

Furthermore, if you do not want to overwrite the trace and logfiles each session, you can set the property:

-Djavaplugin.outputfiles.overwrite=false

If the property is set to false, then trace and logfiles will be uniquely named for each session. If the default traceand log file names are used, then the files would be named asfollows

.plugin.trace.plugin.log

Tracing and logging set through the Control Panel will takeeffect when the Plug-in is launched, but changes made through theControl Panel while a Plug-in is running will have no effect untila restart.

Debugging applets in Java Plug-in

The following options are used when debugging applets in theJava Plug-in.

-Djava.compiler=NONE-Xnoagent-Xdebug-Xrunjdwp:transport=dt_shmem,address=,server=y,suspend=n

The can be any string(example: 2502) which is used by the Java Debugger(jdb) later to connect to the JVM

Default connection timeout

When a connection is made by an applet to a server and theserver doesn't respond properly, the applet may appear to hang andmay also cause the browser to hang, since by default there is nonetwork connection timeout.

To avoid this problem, Java Plug-in 1.4 has added a defaultnetwork timeout value (2 minutes) for all HTTP connections. You canoverride this setting in the Java Runtime Parameters:

-Dsun.net.client.defaultConnectTimeout=

Another networking property that you can set issun.net.client.defaultReadTimeout.

-Dsun.net.client.defaultReadTimeout=

Note

Java Plug-in does not setsun.net.client.defaultReadTimeout by default. If youwant to set it, do so through the Java Runtime Parameters as shownabove.

Networking properties description:

sun.net.client.defaultConnectTimeoutsun.net.client.defaultReadTimeout

These properties specify, respectively, the default connect andread timeout values for the protocol handlers used byjava.net.URLConnection. The default value set by theprotocol handlers is -1, which means there is notimeout set.

sun.net.client.defaultConnectTimeout specifies thetimeout (in milliseconds) to establish the connection to the host.For example, for http connections it is the timeout whenestablishing the connection to the http server. For ftp connectionsit is the timeout when establishing the connection to ftpservers.

sun.net.client.defaultReadTimeout specifies thetimeout (in milliseconds) when reading from an input stream when aconnection is established to a resource.

For the official description of these properties, see Networking Properties.

Security

As of the JDK 7u51 release, the Security panel looks like this:

De-selecting the Enable Java content in the browser button, which is selected by default, will prevent any Java application from running in the browser.

Security Level Slider

When the Enable Java content in the browser option is selected, the Security Level slider becomes available. As the security level is increased, more restrictions are placed on allowing an application to run, and stronger warnings are issued to the user.

The default security level setting is High. The available settings are:

• Very High - Applications that are signed with a valid certificate that is located in the Signer CA keystore, and include the Permissions attribute in the manifest for the main JAR file are allowed to run with security prompts. All other applications are blocked.

• High - Applications that are signed with a valid or expired certificate that is located in the Signer CA keystore, and include the Permissions attribute in the manifest for the main JAR file are allowed to run with security prompts. Applications are also allowed to run with security prompts when the revocation status of the certificate cannot be checked. All other applications are blocked.

• Medium - All applications are allowed to run with security prompts.

See Rich Internet Application Deployment Process for information on how the decision to run or block an application is made.

The Security Level setting affects plug-in applets, Java Web Start applications, embedded JavaFX applications, and access to the native deployment toolkit plug-ins. This setting does not affect stand alone Java applications.

For more information, see Setting the Security Level of the Java Client.

Exception Site List

The exception site list contains a list of URLs that host RIAs that users want to run even if the RIAs are normally blocked by security checks. RIAs from the sites listed are allowed to run with applicable security prompts. Click Edit Site List to add, edit, and remove items.

See Exception Site List for more information.

Deployment Rule Set

If an active deployment rule set is installed on the system, the link View the active Deployment Rule Set is shown before the Manage Certificates button. Click the link to view the rule set. When a rule set is available, the rules determine if a RIA is run without security prompts, run with security prompts, or blocked. For more information on deployment rules, see Deployment Rule Set. For more information on security prompts, see Security Dialogs.

Restore Security Prompts

An option to hide a prompt in the future is included in some security prompts that are shown when an application starts. To insure the continued security of your system, it is recommended that you periodically restore the prompts that were hidden. Seeing the prompts again provides an opportunity to review the applications and ensure that you still want them to run.

To restore the prompts that were previously hidden, click Restore Security Prompts. When asked to confirm the selection, click Restore All. The next time an application is started, the security prompt for that application is shown.

Certificates

Click Manage Certificates to get the Certificates dialog, which looks like this:

Certificate Types

It handles both User- and System-Level(enterprise-wide) certificates of the following types:

• Trusted
• Secure Site
• Signer CA
• Secure site CA
• Client Authentication

TrustedCertificates

These are certificates for signed applets and applications thatare trusted.

Secure site

These are certificates for secure sites.

Signer CA

These are certificates of Certificate Authorities (CAs) forTrusted Certificates; Certificate Authorities are the ones whoissue the certificates to the signers of Trusted Certificates.

Secure site CA

These are certificates of Certificate Authorities (CAs) forsecure sites; Certificate Authorities are the ones who issue thecertificates for secure sites.

ClientAuthentication

These are certificates for a client to authenticate itself to aserver.

User-LevelCertificates

Options

For user-level certificates, there are four options:Import, Export, Remove, and Details.The user can import, export, remove, and view the details of acertificate.

Default Keystore Location

The following table shows the default locations of the of the keystore files.

Operating System	Location
Solaris, Linux, or Mac OS X	${user.home}/.java/deployment/security
Microsoft Windows	${deployment.user.home}\security

For instance, on Microsoft Windows 7, the default location of thekeystore files for user jsmith would beas follows:

C:\Users\jsmith\AppData\LocalLow\Sun\Java\Deployment\security

Non-Default Keystore Location

For non-default locations of the certificatekeystore files, specify them in the User-Leveldeployment.properties file with the following propertynames:

Certificate Type	Property Name
Trusted Certificates	deployment.user.security.trusted.certs
Secure site	deployment.user.security.trusted.jssecerts
Signer CA	deployment.user.security.trusted.cacerts
Secure site CA	deployment.user.security.trusted.jssecacerts
Client Authentication	deployment.user.security.trusted.clientcerts

System-LevelCertificates

Options

For System-Level certificates, the only options a user has areExport and Details.

Default Keystore Location

Trusted, Secure Site, and Client Authentication certificatekeystore files do not exist by default. Thus there areno default locations for them.

The default location for the Signer CA keystore is:

Operating System	Location
Solaris, Linux, or Mac OS X	$JAVA_HOME/lib/security/cacerts
Microsoft Windows	$JAVA_HOME\lib\security\cacerts

The default location for the Secure Site CA keystore is:

Operating System	Location
Solaris, Linux, or Mac OS X	$JAVA_HOME/lib/security/jssecacerts
Microsoft Windows	$JAVA_HOME\lib\security\jssecacerts

Non-Default Keystore Location

The location of the keystore files for the varioustypes of certificates can also be set in a System-Leveldeployment.properties file, if it exists. TheSystem-Level deployment.properties file does not existby default. It is specified in a deployment.configfile. See System-Level deployment.properties file.The following properties may be specified:

Certificate Type	Property Name
Trusted Certificates	deployment.system.security.trusted.certs
Secure site	deployment.system.security.trusted.jssecerts
Signer CA	deployment.system.security.trusted.cacerts
Secure site CA	deployment.system.security.trusted.jssecacerts
Client Authentication	deployment.system.security.trusted.clientcerts

Advanced

The Advanced panel looks like this (three screenshots arerequired to show the entire list of options):

It includes options for Debugging, Java console, Default Java for browsers, Shortcut Creation, JNLP File/MIME Association, Application Installation, Secure Execution Environment, Mixed code security verification, Certificate revocation checks, Advanced Security Settings, and Miscellaneous.

Debugging

You can enable tracing and logging.

JavaConsole

There are three options:

• Show the console
• Hide the console (default)
• Do not start the console

Default Java for Browsers

There are two options; both are selected by default:

• Microsoft Internet Explorer
• Mozilla Family

This option enables settings in your browser that enable you touse the JRE installed in your computer.

For example, if you enable this option for Microsoft InternetExplorer, then the option Use JRE for (requires restart) isavailable, where is the version ofthe JRE installed in your computer. (Find this option by going toTools, then Internet Options,then click the tab Advanced.)

In addition, if you enable this option for Mozilla Family, andyour browser is Firefox, then the extension Java Console appears in theAdd-ons list, where is the version of the JRE installed in yourcomputer. (Access the Add-ons list from theTools menu in the menu bar.)

Shortcut Creation

This provides options for Java Web Start forcreating shortcuts on the desktop. The options are:

• Always allow
• Always allow if hinted
• Prompt user
• Prompt user if hinted (default)
• Never allow

JNLP File/MIME Association

This allows you to associate files with the JNLPMIME type. The options are (radio button, select only one):

• Always allow
• Prompt user (default)
• Never allow

Application Installation

There are four options:

• Install if hinted (default)
• Install if shortcut created
• Install if hinted and shortcut
• Never install

A Java application or applet that is launched with Java WebStart can either be installed or cached on the client computer. Ifthe Java application is cached, then Java Web Start stores theentire application in its cache; the application is removed fromthe client computer when Java Web Start empties its cache. If theJava application is installed, then the application will have anentry in the Add or Remove Programs applet in Windows ControlPanel.

A Java application or applet can specify if it prefers to becached or installed; if the Java application specifies that itprefers to be installed, then it is hinted. By default,Java applications that are hinted are installed on the clientcomputer. You can also specify that a Java application is installedif it creates a shortcut on the client computer's desktop.

Secure Execution Environment

These options are check boxes. You can select any number ofavailable options. All options are checked by default except forthose specified. The following are the various Java securityoptions:

• Allow user to grant permissions to signed content
• Show sandbox warning banner
• Allow user to accept JNLP security requests
• Don't prompt for client certificate selection when nocertificates or only one exists
• Warn if site certificate does not match hostname
• Show site certificate from server even if it is valid (notchecked by default)

Mixed code (sandboxed vs. trusted) security verification

The Mixed code options are radio buttons. Youcan select only one option. For more information, see Mixing Privileged Code and Sandbox Code.

• Enable - show warning if needed (selected by default)
• Enable - hide warning and run with protections
• Enable - hide warning and don't run untrusted code
• Disable verification (not recommended)

Perform certificate revocation checks on

Before a signed applet or Java Web Start application is run, the certificates used to sign the JAR file can be checked to ensure that none have been revoked. You can have all certificates checked, or only the certificate from the publisher of the app. If a certificate has been revoked, any app that is signed with the certificate is not allowed to run. This check can be disabled, but that is not recommended. You can select only one of the following options:

• Publisher's certificate only
• All certificates in the chain of trust (selected by default)
• Do not check (not recommended)

Check for certificate revocation using

The following options indicate what to use to determine if a certificate has been revoked:

• Certificate Revocations Lists (CRLs)
• Online Certificate Status Protocol (OCSP)
• Both CRLs and OCSP (selected by default)

If Do Not Check is selected for Perform certificate revocation checks on, this setting is ignored.

Advanced Security Settings

These options are check boxes. You can select any number ofavailable options. All options are checked by default except forthose specified. The following are the various Java securityoptions:

• Use certificates and keys in browser keystore
• Enable blacklist revocation check
• Enable caching password for authentication
• Use SSL 2.0 compatible ClientHello format (not checked bydefault)
• Use SSL 3.0
• Use TLS 1.0
• Use TLS 1.1 (not checked by default)
• Use TLS 1.2 (not checked by default)

Miscellaneous

The following options are available, none are checked by default:

• Place Java icon in system tray

• Suppress sponsor offers when installing or updating Java

  Select this option if you do not want to be provided with offers from sponsors during the installation or update process.

• Java Quick Starter (Microsoft Windows only)

Command to launch default browser (Solaris, Linux, or Mac OS X only, not shownabove)

Allows you to specify the location of the default browser to belaunched.

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