当前正在使用使用嵌入式Jetty服务器构建的网页，并且无法修改代码以打开跟踪。
结果，试图通过log4j.properties打开跟踪，但无法获取任何跟踪信息。
这是尝试跟踪的错误。 （错误发生在：JspServletWrapper内）
org.apache.jasper.JasperException: java.lang.ClassNotFoundException: org.apache.jsp.index_jsp+
at org.apache.jasper.servlet.JspServletWrapper.getServlet(JspServletWrapper.java:197)+
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:413)+
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386)+
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330)+
at org.eclipse.jetty.jsp.JettyJspServlet.service(JettyJspServlet.java:106)+
JETTY_PATH = / usr / jetty_home
在JETTY_PATH目录中，创建了log4j.properties，并且由于该错误发生在JsServletWrapper中，因此该文件包含以下内容：
注意：由于以前没有配置这种类型的文件，因此不得不使用https://howtodoinjava.com/log4j/how-to-configure-log4j-using-properties-file/中的示例。
log4j.rootLogger=DEBUG, filer
log4j.appender.filer=org.apache.log4j.FileAppender
log4j.appender.filer.layout=org.apache.log4j.PatternLayout
log4j.appender.filer.layout.ConversionPattern=[%d] %p %c - %m%n
log4j.appender.filer.File=/tmp/tmp/jetty.log
log4j.appender.filer.append=true
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=5
log4j.logger.org.apache.jasper.servlet.JspServletWrapper=DEBUG, filer <----Class attempting to trace
log4j.properties文件是否有效和/或位于正确的位置？
对于嵌入式Jetty服务器，是否还需要其他一些配置步骤才能通过log4j.properties获得跟踪？
已编辑以添加Juli内容。
logging.properties放在$ JETTY_PATH中（不确定位置是否正确）
cat logging.properties
handlers = 1catalina.org.apache.juli.FileHandler, 2localhost.org.apache.juli.FileHandler, 3manager.org.apache.juli.FileHandler, 4admin.org.apache.juli.FileHandler, 5host-manager.org.apache.juli.FileHandler, java.util.logging.ConsoleHandler
.handlers = 1catalina.org.apache.juli.FileHandler, java.util.logging.ConsoleHandler
############################################################
# Handler specific properties.
# Describes specific configuration info for Handlers.
############################################################
1catalina.org.apache.juli.FileHandler.level = FINE
1catalina.org.apache.juli.FileHandler.directory = /tmp/tmp/logs
1catalina.org.apache.juli.FileHandler.prefix = catalina.
2localhost.org.apache.juli.FileHandler.level = FINE
2localhost.org.apache.juli.FileHandler.directory = /tmp/tmp/logs
2localhost.org.apache.juli.FileHandler.prefix = localhost.
3manager.org.apache.juli.FileHandler.level = FINE
3manager.org.apache.juli.FileHandler.directory = /tmp/tmp/logs
3manager.org.apache.juli.FileHandler.prefix = manager.
4admin.org.apache.juli.FileHandler.level = FINE
4admin.org.apache.juli.FileHandler.directory = /tmp/tmp/logs
4admin.org.apache.juli.FileHandler.prefix = admin.
5host-manager.org.apache.juli.FileHandler.level = FINE
5host-manager.org.apache.juli.FileHandler.directory = /tmp/tmp/logs
5host-manager.org.apache.juli.FileHandler.prefix = host-manager.
java.util.logging.ConsoleHandler.level = FINE
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter
############################################################
# Facility specific properties.
# Provides extra control for each logger.
############################################################
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].handlers = 2localhost.org.apache.juli.FileHandler
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].handlers = 3manager.org.apache.juli.FileHandler
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/admin].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/admin].handlers = 4admin.org.apache.juli.FileHandler
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/host-manager].handlers = 5host-manager.org.apache.juli.FileHandler
org.apache.jasper.servlet.JspServletWrapper = FINE <-----Class attempting to trace.