<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body><div class="auto-created-dir-div" dir="auto" style="unicode-bidi: embed;"><style>p{margin:0}</style><p><br></p><p>I apologise for the misleading comment about the error message.</p><p><br></p><p>If the bad lookup is picked up by StackMapGenerate (V65) it also prints the code.</p><p>If the bad lookup is picked up by StackCounter (V50) it does not.</p><p><br></p><p>```</p><p>import java.io.IOException;</p><p>import java.lang.constant.ClassDesc;</p><p>import java.lang.constant.MethodTypeDesc;</p><p>import java.nio.file.Files;</p><p>import java.nio.file.Path;</p><p>import java.nio.file.Paths;</p><p>import java.util.List;</p><p>import java.util.ArrayList;</p><p><br></p><p>import java.lang.classfile.*;</p><p>import java.lang.classfile.instruction.*;</p><p><br></p><p>public class CBBuildDup {</p><p><br></p><p> private static void build(CodeBuilder cob) {</p><p> Label L1 = cob.newLabel();</p><p> Label L2 = cob.newLabel();</p><p> SwitchCase sc1 = SwitchCase.of(0,L2); // 0 -> L2</p><p> SwitchCase sc2 = SwitchCase.of(0,L2); // 0 -> L2 Duplicate</p><p>// SwitchCase sc2 = SwitchCase.of(0,L1); // 0 -> L1 Ambiguous</p><p> List<SwitchCase> cases = new ArrayList<>();</p><p><span style="white-space: normal;"><span style="white-space:pre"> </span>cases.add(sc1);</span></p><p> cases.add(sc2);</p><p> cob.iload(0)</p><p> .lookupswitch(L1, cases)</p><p>// .tableswitch(L1, cases)</p><p> .labelBinding(L2)</p><p> .iconst_1()</p><p> .ireturn()</p><p> .labelBinding(L1)</p><p> .iconst_0()</p><p> .ireturn();</p><p> }</p><p> </p><p> public static void main(String[] args) throws IOException {</p><p> byte[] bytes = ClassFile.of()</p><p><span style="white-space: normal;"><span style="white-space:pre"> </span>.build(ClassDesc.of("CBSwitchDup"),</span></p><p> <span style="white-space:pre"> </span>clb -> clb.withFlags(ClassFile.ACC_PUBLIC| ClassFile.ACC_SUPER)</p><p>//<span style="white-space:pre"> </span>.withVersion(50,0) // bad lookup (StackCounter)</p><p><span style="white-space: normal;"><span style="white-space:pre"> </span>.withVersion(65,0) // bad lookup + code dump (StackMapGenerator)</span></p><p> .withMethodBody("table", MethodTypeDesc.ofDescriptor("(I)I"),</p><p> ClassFile.ACC_PUBLIC | ClassFile.ACC_STATIC, CBBuildDup::build));</p><p> <span style="white-space:pre"> </span>for (VerifyError err:ClassFile.of().verify(bytes)) {</p><p><span style="white-space: normal;"><span style="white-space:pre"> </span>System.err.println(err);</span></p><p><span style="white-space: normal;"><span style="white-space:pre"> </span>}</span></p><p><span style="white-space: normal;"><span style="white-space:pre"> </span>Path pathc = Paths.get("CBSwitchDup.class");</span></p><p> Files.write(pathc,bytes);</p><p> }</p><p>}</p><p>```</p><div><br></div></div></body></html>