https://www.graalvm.org/ 
class com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory implements org.graalvm.compiler.lir.framemap.FrameMap$ReferenceMapBuilderFactory
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory
  super_class: java.lang.Object
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory this
         0: .line 861
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/svm/core/graal/amd64/SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory;

  public org.graalvm.compiler.lir.framemap.ReferenceMapBuilder newReferenceMapBuilder(int);
    descriptor: (I)Lorg/graalvm/compiler/lir/framemap/ReferenceMapBuilder;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory this
        start local 1 // int totalFrameSize
         0: .line 864
            new com.oracle.svm.core.heap.SubstrateReferenceMapBuilder
            dup
            iload 1 /* totalFrameSize */
            invokespecial com.oracle.svm.core.heap.SubstrateReferenceMapBuilder.<init>:(I)V
            areturn
        end local 1 // int totalFrameSize
        end local 0 // com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory this
      LocalVariableTable:
        Start  End  Slot            Name  Signature
            0    1     0            this  Lcom/oracle/svm/core/graal/amd64/SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory;
            0    1     1  totalFrameSize  I
    MethodParameters:
                Name  Flags
      totalFrameSize  
}
SourceFile: "SubstrateAMD64Backend.java"
NestHost: com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend
InnerClasses:
  SubstrateReferenceMapBuilderFactory = com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend$SubstrateReferenceMapBuilderFactory of com.oracle.svm.core.graal.amd64.SubstrateAMD64Backend
  public abstract ReferenceMapBuilderFactory = org.graalvm.compiler.lir.framemap.FrameMap$ReferenceMapBuilderFactory of org.graalvm.compiler.lir.framemap.FrameMap