https://tomcat.apache.org/: Tomcat Servlet Engine Core Classes and Standard implementations 
public class org.apache.naming.ResourceEnvRef extends org.apache.naming.AbstractRef
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.apache.naming.ResourceEnvRef
  super_class: org.apache.naming.AbstractRef
{
  private static final long serialVersionUID;
    descriptor: J
    flags: (0x001a) ACC_PRIVATE, ACC_STATIC, ACC_FINAL
    ConstantValue: 1

  public static final java.lang.String DEFAULT_FACTORY;
    descriptor: Ljava/lang/String;
    flags: (0x0019) ACC_PUBLIC, ACC_STATIC, ACC_FINAL
    ConstantValue: "org.apache.naming.factory.ResourceEnvFactory"

  public void <init>(java.lang.String);
    descriptor: (Ljava/lang/String;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=2, locals=2, args_size=2
        start local 0 // org.apache.naming.ResourceEnvRef this
        start local 1 // java.lang.String resourceType
         0: .line 42
            aload 0 /* this */
            aload 1 /* resourceType */
            invokespecial org.apache.naming.AbstractRef.<init>:(Ljava/lang/String;)V
         1: .line 43
            return
        end local 1 // java.lang.String resourceType
        end local 0 // org.apache.naming.ResourceEnvRef this
      LocalVariableTable:
        Start  End  Slot          Name  Signature
            0    2     0          this  Lorg/apache/naming/ResourceEnvRef;
            0    2     1  resourceType  Ljava/lang/String;
    MethodParameters:
              Name  Flags
      resourceType  

  protected java.lang.String getDefaultFactoryClassName();
    descriptor: ()Ljava/lang/String;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.naming.ResourceEnvRef this
         0: .line 48
            ldc "org.apache.naming.factory.ResourceEnvFactory"
            areturn
        end local 0 // org.apache.naming.ResourceEnvRef this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/naming/ResourceEnvRef;
}
SourceFile: "ResourceEnvRef.java"