[Fixed] org.apache.tomcat.util.bcel.classfile.classformatexception: invalid byte tag in constant pool: 19

1. ClassFormatException: Invalid byte tag in constant pool: 15 Overview

In this tutorial, We'll learn how to fix org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15. This is a common issue while working with Tomcat 7 or Tomcat 8 version. We'll provide you the various solutions to fix this error permanently.

Addition to this issue, you can find the other set of trouble shooting problems.

[Fixed] Java 8: Invalid byte tag in constant pool: 15 or 19 - Tomcat

Common issues on the same error. The solution is common in all cases.

Invalid byte tag in constant pool: 15
Invalid byte tag in constant pool: 16
Invalid byte tag in constant pool: 18
Invalid byte tag in constant pool: 19

Let me tell my store with this problem and how did the troubleshoot this issue.

org.apache.tomcat.util.bcel.classfile.classformatexception: invalid byte tag in constant pool: 19

I have started working with java version 1.7 and Apache Tomcat/7.0.12. After some time my mind was completely changed. Felt very curious really waiting to work with java 8 features.

Read the article on Java 8 Lambda Expressions Feature

But, Later did the analysis and have just updated java version to 1.8 (C:\Program Files\Java\jdk1.8.0_51).

Finally, restarted my tomcat server then appeared exception with the following full error stack trace.

An exception occurred after Tomcat 7 or Tomcat 8 restart:

Aug 22, 2015 10:57:05 AM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.12
org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15
    at org.apache.tomcat.util.bcel.classfile.Constant.readConstant(Constant.java:131)
    at org.apache.tomcat.util.bcel.classfile.ConstantPool.(ConstantPool.java:60)
    at org.apache.tomcat.util.bcel.classfile.ClassParser.readConstantPool(ClassParser.java:209)
    at org.apache.tomcat.util.bcel.classfile.ClassParser.parse(ClassParser.java:119)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:1917)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1806)
    at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1765)
    at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1751)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1255)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:882)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:317)
    at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:89)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5081)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:774)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1033)
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:291)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:727)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:620)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:303)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:431)

d tomcat official website. Stated that "The "offical answer" is that Tomcat 7 runs on Java 8, see http://tomcat.apache.org/whichversion.html ("Java version 6 and later")."

2. Solution 1 - web.xml

However, if annotation scanning is enabled (metadata-complete="true" in web.xml) there are some issues due to BCEL (not able to process the new Java 8 byte codes). You will get exceptions like (at least with Tomcat 7):

SEVERE: Unable to process Jar entry [jdk/nashorn/internal/objects/NativeString.class] from Jar [jar:file:/usr/lib/jvm/jdk1.8.0_5/jre/lib/ext/nashorn.jar!/] for annotations
org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15
    at org.apache.tomcat.util.bcel.classfile.Constant.readConstant(Constant.java:131)

If not using annotation scanning, everything works fine, starting release 7.0.53 (updated compiler with better Java 8 support).

(UPDATE 2014-10-17) If your are using annotation scanning and your own code is not Java 8 based, another solution is to add the following line in /etc/tomcat7/catalina.properties (text added after "ant-launcher.jar" so part of property tomcat.util.scan.DefaultJarScanner.jarsToSkip):

junit.jar,junit-*.jar,ant-launcher.jar,\
jfxrt.jar,nashorn.jar

Tested with Tomcat 7.0.28 and Oracle JDK 8_25 on Debian 7.6.

3. Solution 2 - Tomcat upgrade to latest

Upgrade the tomcat version to Tomcat 7.0.65. Works well.

Solution 2 is simple, definitely works.

There are some more scenarios which causes the same problem which is below case and another case as well. We have provided other alternative solutions based many user experiences. Hope helps.
Problem: Tomcat 7 - Servlet 3.0: Invalid byte tag in constant pool:

I just switched the web.xml to servlet 3.0 (from a app running 2.4 previously) and now I'm seeing the following error (turned on fine logging for org.apache.tomcat.util):

Following is the problem requirements.

tomcat 7.0.16
Java 1.6.0_22
CentOS 5.6

Error occured for ClassFormatException:

mtyson  FINE: Scanning JAR [file:/usr/java/jdk1.6.0_22/jre/lib/ext/jcharset.jar] from classpath
mtyson  Jul 19, 2011 10:04:40 AM org.apache.catalina.startup.HostConfig deployDirectory
mtyson  SEVERE: Error deploying web application directory ROOT
mtyson  org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 60

4. Solution 3 - Problem with IBM library

It may not be your issue, but mine was the same as this one -- an old version of com.ibm.icu:icu4j. I solved the problem by changing by build configuration to exclude the older transitive dependencies and explicitly depending upon the latest version (4.8).


I was facing the same issue from a week and resolved by simply replacing the icu4j.2.1.jar file with latest version of jar.

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>com.ibm.icu</groupId>
            <artifactId>icu4j</artifactId>
            <version>3.4.4</version>
        </dependency>
    </dependencies>
</dependencyManagement>

5. Solution 4 - COOKIE

Notice the use of the version="2.5" with the web-app_3_0.xsd schema and the presence of the session-config tracking-mode which is only part of the 3.0 spec not the 2.5 (AFAIK)

Add the below code in web.xml file.

<session-config>
        <tracking-mode>COOKIE</tracking-mode>
</session-config>

6. Conclusion

In this article, We've learn how to fix "Invalid byte tag in constant pool: 15" error. And more provided 4 ways to solve this error with examples.

References:

StackOverFlow 1
StackOverFlow 2
MkYong