https://www.graalvm.org/ 
class com.oracle.svm.jni.functions.JNIFunctions$Support$JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.svm.jni.functions.JNIFunctions$Support$JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue
  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.jni.functions.JNIFunctions$Support$JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue this
         0: .line 1009
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.svm.jni.functions.JNIFunctions$Support$JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/svm/jni/functions/JNIFunctions$Support$JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue;

  static void enter(com.oracle.svm.jni.nativeapi.JNIJavaVM);
    descriptor: (Lcom/oracle/svm/jni/nativeapi/JNIJavaVM;)V
    flags: (0x0008) ACC_STATIC
    Code:
      stack=2, locals=1, args_size=1
        start local 0 // com.oracle.svm.jni.nativeapi.JNIJavaVM vm
         0: .line 1011
            aload 0 /* vm */
            invokeinterface com.oracle.svm.jni.nativeapi.JNIJavaVM.getFunctions:()Lcom/oracle/svm/jni/nativeapi/JNIInvokeInterface;
            invokeinterface com.oracle.svm.jni.nativeapi.JNIInvokeInterface.getIsolate:()Lorg/graalvm/nativeimage/Isolate;
            iconst_1
            invokestatic com.oracle.svm.core.c.function.CEntryPointActions.enterAttachThread:(Lorg/graalvm/nativeimage/Isolate;Z)I
            ifeq 2
         1: .line 1012
            invokestatic com.oracle.svm.jni.nativeapi.JNIErrors.JNI_ERR:()I
            i2l
            invokestatic com.oracle.svm.core.c.function.CEntryPointActions.bailoutInPrologue:(J)V
         2: .line 1014
      StackMap locals:
      StackMap stack:
            return
        end local 0 // com.oracle.svm.jni.nativeapi.JNIJavaVM vm
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    3     0    vm  Lcom/oracle/svm/jni/nativeapi/JNIJavaVM;
    MethodParameters:
      Name  Flags
      vm    
}
SourceFile: "JNIFunctions.java"
NestHost: com.oracle.svm.jni.functions.JNIFunctions
InnerClasses:
  Support = com.oracle.svm.jni.functions.JNIFunctions$Support of com.oracle.svm.jni.functions.JNIFunctions
  JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue = com.oracle.svm.jni.functions.JNIFunctions$Support$JNIJavaVMEnterAttachThreadEnsureJavaThreadPrologue of com.oracle.svm.jni.functions.JNIFunctions$Support