https://www.graalvm.org/ 
public interface org.graalvm.component.installer.ComponentCatalog$DownloadInterceptor
  minor version: 0
  major version: 59
  flags: flags: (0x0601) ACC_PUBLIC, ACC_INTERFACE, ACC_ABSTRACT
  this_class: org.graalvm.component.installer.ComponentCatalog$DownloadInterceptor
  super_class: java.lang.Object
{
  public abstract org.graalvm.component.installer.remote.FileDownloader processDownloader(org.graalvm.component.installer.model.ComponentInfo, org.graalvm.component.installer.remote.FileDownloader);
    descriptor: (Lorg/graalvm/component/installer/model/ComponentInfo;Lorg/graalvm/component/installer/remote/FileDownloader;)Lorg/graalvm/component/installer/remote/FileDownloader;
    flags: (0x0401) ACC_PUBLIC, ACC_ABSTRACT
    MethodParameters:
      Name  Flags
      info  
      dn    

  public org.graalvm.component.installer.persist.MetadataLoader interceptMetadataLoader(org.graalvm.component.installer.model.ComponentInfo, org.graalvm.component.installer.persist.MetadataLoader);
    descriptor: (Lorg/graalvm/component/installer/model/ComponentInfo;Lorg/graalvm/component/installer/persist/MetadataLoader;)Lorg/graalvm/component/installer/persist/MetadataLoader;
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=3, args_size=3
        start local 0 // org.graalvm.component.installer.ComponentCatalog$DownloadInterceptor this
        start local 1 // org.graalvm.component.installer.model.ComponentInfo info
        start local 2 // org.graalvm.component.installer.persist.MetadataLoader delegate
         0: .line 90
            aload 2 /* delegate */
            areturn
        end local 2 // org.graalvm.component.installer.persist.MetadataLoader delegate
        end local 1 // org.graalvm.component.installer.model.ComponentInfo info
        end local 0 // org.graalvm.component.installer.ComponentCatalog$DownloadInterceptor this
      LocalVariableTable:
        Start  End  Slot      Name  Signature
            0    1     0      this  Lorg/graalvm/component/installer/ComponentCatalog$DownloadInterceptor;
            0    1     1      info  Lorg/graalvm/component/installer/model/ComponentInfo;
            0    1     2  delegate  Lorg/graalvm/component/installer/persist/MetadataLoader;
    MethodParameters:
          Name  Flags
      info      
      delegate  
}
SourceFile: "ComponentCatalog.java"
NestHost: org.graalvm.component.installer.ComponentCatalog
InnerClasses:
  public abstract DownloadInterceptor = org.graalvm.component.installer.ComponentCatalog$DownloadInterceptor of org.graalvm.component.installer.ComponentCatalog