# Apache Tomcat 7

Version 7.0.4, Oct 14 2010

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Global Settings

- System properties

# System Properties

Table of Contents

> - Introduction
> - Property replacements
> - Clustering
> - Expression Language
> - Jasper
> - Security
> - Specification
> - Sessions
> - Logging
> - Other

Introduction

> The following sections list the system properties that may be set to modify the default Tomcat behaviour.

Property replacements

> Property | Description
> --- | ---
> `org.apache.tomcat.util.digester. PROPERTY_SOURCE` | Set this to a fully qualified name of a class that implements `org.apache.tomcat.util.IntrospectionUtils.PropertySource`. Required to have a public constructor with no arguments. Use this to add a property source, that will be invoked when `${parameter}` denoted parameters are found in the XML files that Tomcat parses.

Clustering

> Property | Description
> --- | ---
> `org.apache.catalina. tribes.dns_lookups` | If `true`, the clustering module will attempt to use DNS to resolve any host names provided in the cluster configuration. If not specified, the default value of `false` will be used.

Expression Language

> Property | Description
> --- | ---
> `org.apache.el.parser.COERCE_TO_ZERO` | If `true`, when coercing expressions to numbers `""` and `null` will be coerced to zero as required by the specification. If not specified, the default value of `true` will be used.
> `org.apache.el.parser.SKIP_IDENTIFIER_CHECK` | If `true`, when parsing expressions, identifiers will not be checked to ensure that they conform to the Java Language Specification for Java identifiers. If not specified, the default value of `false` will be used.
> `org.apache.el.BeanELResolver.CACHE_SIZE` | The number of javax.el.BeanELResolver.BeanProperties objects that will be cached by the EL Parser. If not specified, the default of `1000` will be used.
> `org.apache.el.ExpressionBuilder.CACHE_SIZE` | The number of parsed EL expressions that will be cached by the EL Parser. If not specified, the default of `5000` will be used.

Jasper

> Property | Description
> --- | ---
> `org.apache.jasper.compiler. Generator.VAR_EXPRESSIONFACTORY` | The name of the variable to use for the expression language expression factory. If not specified, the default value of `_el_expressionfactory` will be used.
> `org.apache.jasper.compiler. Generator.VAR_INSTANCEMANAGER` | The name of the variable to use for the instance manager factory. If not specified, the default value of `_jsp_instancemanager` will be used.
> `org.apache.jasper.compiler. Generator.STRICT_GET_PROPERTY` | If `true`, the requirement to have the object referenced in `jsp:getProperty` action to be previously "introduced" to the JSP processor, as specified in the chapter JSP.5.3 of JSP 2.0 and later specifications, is enforced. If not specified, the specification compliant default of `true` will be used.
> `org.apache.jasper.compiler. Parser.STRICT_QUOTE_ESCAPING` | If `false` the requirements for escaping quotes in JSP attributes will be relaxed so that an unescaped quote will not cause an error. If not specified, the specification compliant default of `true` will be used.
> `org.apache.jasper.runtime. BodyContentImpl.LIMIT_BUFFER` | If `true`, any tag buffer that expands beyond `org.apache.jasper.Constants.DEFAULT_TAG_BUFFER_SIZE` will be destroyed and a new buffer created of the default size. If not specified, the default value of `false` will be used.
> `org.apache.jasper.runtime. JspFactoryImpl.USE_POOL` | If `true`, a ThreadLocal `PageContext` pool will be used. If not specified, the default value of `true` will be used.
> `org.apache.jasper.runtime. JspFactoryImpl.POOL_SIZE` | The size of the ThreadLocal `PageContext`. If not specified, the default value of `8` will be used.
> `org.apache.jasper.Constants. JSP_SERVLET_BASE` | The base class of the Servlets generated from the JSPs. If not specified, the default value of `org.apache.jasper.runtime.HttpJspBase` will be used.
> `org.apache.jasper.Constants. SERVICE_METHOD_NAME` | The name of the service method called by the base class. If not specified, the default value of `_jspService` will be used.
> `org.apache.jasper.Constants. SERVLET_CLASSPATH` | The name of the ServletContext attribute that provides the classpath for the JSP. If not specified, the default value of `org.apache.catalina.jsp_classpath` will be used.
> `org.apache.jasper.Constants. JSP_FILE` | The name of the request attribute for `<jsp-file>` element of a servlet definition. If present on a request, this overrides the value returned by `request.getServletPath()` to select the JSP page to be executed. If not specified, the default value of `org.apache.catalina.jsp_file` will be used.
> `org.apache.jasper.Constants. PRECOMPILE` | The name of the query parameter that causes the JSP engine to just pregenerate the servlet but not invoke it. If not specified, the default value of `org.apache.catalina.jsp_precompile` will be used.
> `org.apache.jasper.Constants. JSP_PACKAGE_NAME` | The default package name for compiled jsp pages. If not specified, the default value of `org.apache.jsp` will be used.
> `org.apache.jasper.Constants. TAG_FILE_PACKAGE_NAME` | The default package name for tag handlers generated from tag files. If not specified, the default value of `org.apache.jsp.tag` will be used.
> `org.apache.jasper.Constants. ALT_DD_ATTR` | The servlet context attribute under which the alternate deployment descriptor for this web application is stored. If not specified, the default value of `org.apache.catalina.deploy.alt_dd` will be used.
> `org.apache.jasper.Constants. TEMP_VARIABLE_NAME_PREFIX` | Prefix to use for generated temporary variable names. If not specified, the default value of `_jspx_temp` will be used.
> `org.apache.jasper.Constants. USE_INSTANCE_MANAGER_FOR_TAGS` | If `true`, the instance manager is used to obtain tag handler instances. If not specified, `false` will be used.

Security

> Property | Description
> --- | ---
> `org.apache.catalina.connector. RECYCLE_FACADES` | If this is `true` or if a security manager is in use a new facade object will be created for each request. If not specified, the default value of `false` will be used.
> `org.apache.catalina.connector. CoyoteAdapter.ALLOW_BACKSLASH` | If this is `true` the '\' character will be permitted as a path delimiter. If not specified, the default value of `false` will be used.
> `org.apache.tomcat.util.buf. UDecoder.ALLOW_ENCODED_SLASH` | If this is `true` '%2F' and '%5C' will be permitted as path delimiters. If not specified, the default value of `false` will be used.

Specification

> Property | Description
> --- | ---

> `org.apache.catalina. STRICT_SERVLET_COMPLIANCE`

> If this is `true` the default values will be changed for:
> - `org.apache.catalina.core.ApplicationContext.GET_RESOURCE_REQUIRE_SLASH`
> - `org.apache.catalina.core.ApplicationDispatcher.WRAP_SAME_OBJECT`
> - `org.apache.catalina.core.StandardHostValve.ACCESS_SESSION`
> - `org.apache.catalina.session.StandardSession.ACTIVITY_CHECK`
> - `org.apache.catalina.session.StandardSession.LAST_ACCESS_AT_START`
> - `org.apache.tomcat.util.http.ServerCookie.ALWAYS_ADD_EXPIRES`.
> - `org.apache.tomcat.util.http.ServerCookie.FWD_SLASH_IS_SEPARATOR`.
> - `org.apache.tomcat.util.http.ServerCookie.STRICT_NAMING`.
> - The `tldNamespaceAware` attribute of any Context element.
> - The `tldValidation` attribute of any Context element.
> - The `xmlNamespaceAware` attribute of any Context element.
> - The `xmlValidation` attribute of any Context element.

> Note that changing a number of the above defaults is likely to break the majority of systems as some browsers are unable to correctly handle the cookie headers that result from a strict adherence to the specifications. Defaults, regardless of whether or not they have been changed by setting `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` can always be overridden by explicitly setting the appropriate system property or element attribute.

> `org.apache.catalina.connector. Response.ENFORCE_ENCODING_IN_GET_WRITER`

> If this is `true` then a call to `Response.getWriter()` if no character encoding has been specified will result in subsequent calls to `Response.getCharacterEncoding()` returning `ISO-8859-1` and the `Content-Type` response header will include a `charset=ISO-8859-1` component. (SRV.15.2.22.1)
> If not specified, the default specification compliant value of `true` will be used.

> `org.apache.catalina.core. ApplicationContext.GET_RESOURCE_REQUIRE_SLASH`

> If this is `true` then the path passed to `ServletContext.getResource()` or `ServletContext.getResourceAsStream()` must start with "/". If `false`, code like `getResource("myfolder/myresource.txt")` will work. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.

> `org.apache.catalina.core. ApplicationDispatcher.WRAP_SAME_OBJECT` | If this is `true` then any wrapped request or response object passed to an application dispatcher will be checked to ensure that it has wrapped the original request or response. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.
> `org.apache.tomcat.util.http. ServerCookie.ALLOW_EQUALS_IN_VALUE` | If this is `true` Tomcat will allow `=` characters when parsing unquoted cookie values. If `false`, cookie values containing `=` will be terminated when the `=` is encountered and the remainder of the cookie value will be dropped. If not specified, the default value specification compliant value of `false` will be used.
> `org.apache.tomcat.util.http. ServerCookie.ALLOW_HTTP_SEPARATORS_IN_V0` | If this is `true` Tomcat will allow HTTP separators in cookie names and values. If not specified, the default specification compliant value of `false` will be used.

> `org.apache.tomcat.util.http. ServerCookie.ALWAYS_ADD_EXPIRES`

> If this is `true` Tomcat will always add an expires parameter to a SetCookie header even for cookies with version greater than zero. This is to work around a known IE6 and IE7 bug that causes IE to ignore the Max-Age parameter in a SetCookie header. If not specified, the default value will be used. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `false`, else the default value will be `true`.

> `org.apache.tomcat.util.http. ServerCookie.FWD_SLASH_IS_SEPARATOR`

> If this is true then the `/` (forward slash) character will be treated as a separator. Note that this character is frequently used in cookie path attributes and some browsers will fail to process a cookie if the path attribute is quoted as is required by a strict adherence to the specifications. This is highly likely to break session tracking using cookies. If not specified, the default value will be used. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.

> `org.apache.tomcat.util.http. ServerCookie.STRICT_NAMING`

> If this is true then the requirements of the Servlet specification that Cookie names must adhere to RFC2109 (no use of separators) will be enforced. If not specified, the default value will be used. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.

Sessions

> Property | Description
> --- | ---
> `org.apache.catalina.SSO_SESSION_COOKIE_NAME` | An alternative name for the single sign on session cookie. Defaults to `JSESSIONIDSSO`.

> `org.apache.catalina.core. StandardHostValve.ACCESS_SESSION`

> If this is `true`, every request that is associated with a session will cause the session's last accessed time to be updated regardless of whether or not the request explicitly accesses the session. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.

> `org.apache.catalina.session. StandardSession.ACTIVITY_CHECK`

> If this is `true`, Tomcat will track the number of active requests for each session. When determining if a session is valid, any session with at least one active request will always be considered valid. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.

> `org.apache.catalina.session. StandardSession.LAST_ACCESS_AT_START`

> If this is `true`, the last accessed time for sessions will be calculated from the beginning of the previous request. If `false`, the last accessed time for sessions will be calculated from the end of the previous request. This also affects how the idle time is calculated. If `org.apache.catalina.STRICT_SERVLET_COMPLIANCE` is set to `true`, the default of this setting will be `true`, else the default value will be `false`.

Logging

> Property | Description
> --- | ---

> `org.apache.juli.AsyncOverflowDropType`

> When the memory limit of records has been reached the system needs to determine what action to take. Currently there are three actions that can be taken:
> - `int OVERFLOW_DROP_LAST = 1` - the record that caused the overflow will be dropped and not logged
> - `int OVERFLOW_DROP_FIRST = 2` - the record that is next in line to be logged will be dropped to make room for the latest record on the queue
> - `int OVERFLOW_DROP_FLUSH = 3` - suspend the thread while the queue empties out and flushes the entries to the write buffer
> - `int OVERFLOW_DROP_CURRENT = 4` - drop the current log entry
> Default value is `1` (OVERFLOW_DROP_LAST).

> `org.apache.juli.AsyncMaxRecordCount`

> The max number of log records that the async logger will keep in memory. When this limit is reached and a new record is being logged by the JULI framework the system will take an action based on the `org.apache.juli.AsyncOverflowDropType` setting. The default value is `10000` records.
> This number represents the global number of records, not on a per handler basis.

> `org.apache.juli.AsyncLoggerPollInterval` | The poll interval in milliseconds for the asynchronous logger thread in milliseconds. If the log queue is empty, the async thread will issue a poll(poll interval) in order to not wake up to often. The default value is `1000` milliseconds.

Other

> Property | Description
> --- | ---
> `org.apache.coyote. USE_CUSTOM_STATUS_MSG_IN_HEADER` | If this is `true`, custom HTTP status messages will be used within HTTP headers. If a custom message is specified that is not valid for use in an HTTP header (as defined by RFC2616) then the custom message will be ignored and the default message used. If not specified, the default value of `false` will be used.
> `catalina.useNaming` | If this is `false` it will override the `useNaming` attribute for all Context elements.
> `jvmRoute` | Provides a default value for the `jvmRoute` attribute of the Engine element. It does not override the value configured on the Engine element.
> `catalina.config` | The URL for the catalina.properties configuration file.
> `tomcat.util.buf.StringCache.byte.enabled` | If `true`, the String cache is enabled for `ByteChunk`. If not specified, the default value of `false` will be used.
> `tomcat.util.buf.StringCache.char.enabled` | If `true`, the String cache is enabled for `CharChunk`. If not specified, the default value of `false` will be used.
> `tomcat.util.buf.StringCache.trainThreshold` | The number of times `toString()` must be called before the cache is activated. If not specified, the default value of `20000` will be used.
> `tomcat.util.buf.StringCache.cacheSize` | The size of the String cache. If not specified, the default value of `200` will be used.
> `tomcat.util.buf.StringCache.maxStringSize` | The maximum length of String that will be cached. If not specified, the default value of `128` will be used.
> `org.apache.tomcat.util. http.FastHttpDateFormat.CACHE_SIZE` | The size of the cache to use parsed and formatted date value. If not specified, the default value of `1000` will be used.
> `org.apache.tomcat.util. net.NioSelectorShared` | If `true`, use a shared selector for servlet write/read. If not specified, the default value of `true` will be used.
> `org.apache.catalina.startup. EXIT_ON_INIT_FAILURE` | If `true`, the server will exit if an exception happens during the server initialization phase. The default is `false`.

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