Tomcat 9.0.34 / JDT 4.15 jsp compile error

[Markus Fömpe]

Hi,

With Tomcat 9.0.34 the JDT compiler was updated to 4.15.
Since then, there is an error when Tomcat compiles the JSP at runtime when this 
construct is used in a JSP:

<%@ page import="java.util.List"%>
<%@ page import="java.util.ArrayList"%>
<%
class InnerClass {
    // some class members
}

List<InnerClass> list = new ArrayList<>();

for(InnerClass elements : list) {
    // do sth
}
%>


This is root cause:

java.lang.ClassCastException: class 
org.eclipse.jdt.internal.compiler.lookup.PlainPackageBinding cannot be cast to 
class org.eclipse.jdt.internal.compiler.lookup.TypeBinding 
(org.eclipse.jdt.internal.compiler.lookup.PlainPackageBinding and 
org.eclipse.jdt.internal.compiler.lookup.TypeBinding are in unnamed module of 
loader java.net.URLClassLoader @20398b7c)
        
org.eclipse.jdt.internal.compiler.ClassFile.getTypeBinding(ClassFile.java:5941)
        
org.eclipse.jdt.internal.compiler.ClassFile.traverse(ClassFile.java:7011)
        
org.eclipse.jdt.internal.compiler.ClassFile.generateStackMapTableAttribute(ClassFile.java:4826)
        
org.eclipse.jdt.internal.compiler.ClassFile.completeCodeAttribute(ClassFile.java:1519)
        
org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.generateCode(AbstractMethodDeclaration.java:357)
        
org.eclipse.jdt.internal.compiler.ast.AbstractMethodDeclaration.generateCode(AbstractMethodDeclaration.java:281)
        
org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.generateCode(TypeDeclaration.java:579)
        
org.eclipse.jdt.internal.compiler.ast.TypeDeclaration.generateCode(TypeDeclaration.java:649)
        
org.eclipse.jdt.internal.compiler.ast.CompilationUnitDeclaration.generateCode(CompilationUnitDeclaration.java:412)
        org.eclipse.jdt.internal.compiler.Compiler.process(Compiler.java:912)
        
org.eclipse.jdt.internal.compiler.Compiler.processCompiledUnits(Compiler.java:575)
        org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:475)
        org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:426)
        
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:528)
        org.apache.jasper.compiler.Compiler.compile(Compiler.java:392)
        org.apache.jasper.compiler.Compiler.compile(Compiler.java:362)
        org.apache.jasper.compiler.Compiler.compile(Compiler.java:346)
        
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:605)
        
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:400)
        org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
        org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
        javax.servlet.http.HttpServlet.service(HttpServlet.java:741)


If the JSP is precompiled using an ant task and the JDT compiler, the error 
doesn’t occur:

<javac srcdir="${basedir}/work"
    destdir="${basedir}/work"
    debug="${compile.debug}"
    deprecation="${compile.deprecation}"
    optimize="${compile.optimize}"
    includeantruntime="false"
    target="${java.version}"
    source="${java.version}">
    <classpath refid="compile.classpath"/>
    <compilerarg compiler="org.eclipse.jdt.core.JDTCompilerAdapter" />
</javac>

I know that the error is within the JDT Stacktrace, but because this error 
doesn’t occur when using the JDT for compiling the generated Java file, I 
assume that this problem is related to a Tomcat configuration. I use the docker 
image tomcat:9.0.34.
If required I can also provide the Java source generated from the JSP.

Best regards,
Markus