Embedded tomcat giving failed to scan jars from classloader hierarchy

Solution 1:

One option is to include server.tomcat.additional-tld-skip-patterns=*.jar within the application.properties file, while another option is to include server: tomcat: additional-tld-skip-patterns: '*.jar'within the application.yml file.
The component known as "Jar Scanner" and the response given by the official source are being referred to.

Solution 2:

The dependency hierarchy does not suggest that xml-apis.jar is required by tomcat-embed-core, so it should not be assumed.
To fix the error, ensure that the scope of the xml-apis.jar is not set to "provided". Next, delete all the files located under C:/Users/raghavender.n/.m2/repository/xalan/xalan/ and run "mvn clean install". Finally, verify if the xml-apis.jar is present.
If you are searching for information on Spring Web Application that utilizes an embedded Tomcat but does not employ Spring Boot, you can find helpful insights in this post.

Solution 3:

To find a solution, add the subsequent line to the catalina.properties file.
tomcat.util.scan.StandardJarScanFilter.jarsToSkip=*.jar
Java - shared classloader with embedded Tomcat 8, 2 You could try using the setDelegate method in StandardContext to prevent the web-app classloader from reloading the Counter class, but this impacts security in a bad manner so I advice against that. The usual way to expose statistics is to use JMX (MBeans). You enable this by calling the setUseNaming method in …

Java.io.FileNotFoundException: /tomcat/lib/webservices-api.jar

Solution 1:

Starting from Tomcat 8.0.38, there is a flag named scanManifest that allows scanning additional classpath entries from jars' MANIFEST.MF file. The default is set to true, meaning that the manifest of jars is scanned. To avoid issues, it is recommended to verify whether you have any jar that refers to this jar file using the CLASS-PATH entry in the MANIFEST.MF. I faced a similar issue before.

May 07, 2019 11:33:21 AM org.apache.tomcat.util.scan.StandardJarScanner processURLs
WARNING: Failed to scan [file:/C:/apache-tomcat-9.0.8/lib/jaxws-api.jar] from classloader hierarchy
java.io.FileNotFoundException: C:\apache-tomcat-9.0.8\lib\jaxws-api.jar (The system cannot find the file specified)

I noticed that my jar file named jaxws-rt-2.1.3 has jaxws-api.jar included in its class path. However, since I already have jaxws-api-2.1.jar in my lib, the jarscanner raised an error of "File not found" because it was searching for a versionless file.
By including the given entry in context.xml located under TOMCAT_HOME/conf, the issue of resolving non-existent jar files can be resolved.

Another way to deploy the application is by rectifying the manifest file to comprise the jar version.

Solution 2:

The implementation of the given specification is present in webservices-rt-xxx.jar and it should be noted that it is different from webservices-api.jar .

It is recommended to add the second jar to your lib directory as well.

Java.io.FileNotFoundException: /tomcat/lib/webservices, In Tomcat 8.0.38 and onwards we have one flag called scanManifest to scan the additional classpath entries from the MANIFEST.MF of the jars. The default is true i.e. to scan the manifest of jars.

Check if you have any jar with CLASS-PATH entry in MANIEST.MF referring this jar file. I got the similar issue Code sampleMay 07, 2019 11:33:21 AM org.apache.tomcat.util.scan.StandardJarScanner processURLs

WARNING: Failed to scan [file:/C:/apache-tomcat-9.0.8/lib/jaxws-api.jar] from classloader hierarchyjava.io.FileNotFoundException: C:\apache-tomcat-9.0.8\lib\jaxws-api.jar (The system cannot find the file specified)Feedback

AFTER upgrade from Spring boot 1.2 to 1.5.2, FileNotFoundException during Tomcat 8.5 Startup

Solution 1:

RootCause:
According to the Tomcat Wiki, during server startup, the Servlet 3.0 specification mandates the scanning of Jars.

For this intention, Tomcat is employing the StandardJarScanner from org.apache.tomcat.util.scan.

From the documentation of the class called StandardJarScanner.

The JarScanner implementation, by default, examines the contents of the WEB-INF/lib directory, followed by the classloader provided. After that, it traverses up the classloader hierarchy. This approach fulfills the requirements of the Servlet 3.0 specification and includes various Tomcat-specific extensions. These extensions are as follows:
By default, the classloader hierarchy is scanned, while checking all files for JARs is not enabled.
By default, the feature that tests for exploded JARs in all directories is disabled.
The configuration controls all of the available extensions.

• Option 1: Tailored for Spring Boot.

It is possible to turn off the scanning of this jar.

To disable it, I included a property in the application-xxx.properties file that is specific to Spring Boot.

# Comma-separated list of additional patterns that match jars to ignore for TLD scanning.    
`server.tomcat.additional-tld-skip-patterns=*.jar`

Tomcat offers comparable properties that can be found at this location.

The aforementioned attributes can be employed to set up traditional Tomcat applications that are not based on Spring Boot.

• Alternative 2: Tailored for Spring Framework

As a solution, you can turn off the JarScanner specifically for manifest files.

@Bean
public EmbeddedServletContainerFactory embeddedServletContainerFactory() {
  return new TomcatEmbeddedServletContainerFactory() {
    @Override
    protected void postProcessContext(Context context) {
      ((StandardJarScanner) context.getJarScanner()).setScanManifest(false);
    }
  };
}

• Option 3: Conventional Independent Tomcat.

...

...

The component being referred to is the Jar Scanner.

Solution 2:

To enhance Sundaraj's discoveries, it is not recommended to entirely turn off TLD scanning as it might cause a disruption in the support of JSP/JSTL.

The problem lies in the fact that although the classpath is fine, Tomcat examines the manifest files of each Jar. This causes meaningless paths to be generated when using Maven because every Jar is located in its own directory, which is likely to occur when running from Eclipse.

To continue using JSP alongside JSTL, it is recommended to only deactivate the scanning of the manifest.

To configure your application for Spring Boot 2.0, include the following in your application's settings.

  @Bean
  public TomcatServletWebServerFactory tomcatFactory() {
    return new TomcatServletWebServerFactory() {
      @Override
      protected void postProcessContext(Context context) {
        ((StandardJarScanner) context.getJarScanner()).setScanManifest(false);
      }
    };
  }

Solution 3:

We must configure the StandardJarScanner loaded by JarScannerFactory in order to ensure compatibility with spring boot 2.1.8.

import org.apache.tomcat.JarScanner;
import org.apache.tomcat.util.scan.StandardJarScanner;
import org.springframework.boot.web.servlet.ServletContextInitializer;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class WebContextConfiguration {
    @Bean
    public ServletContextInitializer servletContextInitializer() {
        return context -> context.setAttribute(
                JarScanner.class.getName(),
                new StandardJarScanner() {{
                    setScanManifest(false);
                }}
        );
    }
}

Tomcat8 - Resource locking in embedded tomcat, I don't find any method for this. I use embedded tomcat 8.5.8. Stack Overflow. About; Products For Teams; Stack Overflow Tomcat 8 throwing - org.apache.catalina.webresources.Cache.getResource Unable to add the resource Invalid character found in method name. HTTP method names must be …

Which of the following method is called immediately after the re-render

component did update arguments

componentDidUpdate(prevProps, prevState) {
  // only update chart if the data has changed
  if (prevProps.data !== this.props.data) {
    this.chart = c3.load({
      data: this.props.data
    });
  }
}

lifecycles if reactjs

class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {date: new Date()};
  }
  componentDidMount() {  }
  componentWillUnmount() {  }
  render() {
    return (
      

        
Hello, world!

        
It is {this.state.date.toLocaleTimeString()}.

      

    );
  }
}

AFTER upgrade from Spring boot 1.2 to 1.5.2, Testing all directories to see if they are exploded JARs (disabled by default) All of the extensions may be controlled via configuration. Solution1: Spring Boot specific. We can disablethis jar scanning. I disabled it by adding below property in application-xxx.properties file. This property is Spring Boot specific.