https://tomcat.apache.org/: Tomcat Servlet Engine Core Classes and Standard implementations 
public class org.apache.catalina.startup.AddPortOffsetRule extends org.apache.tomcat.util.digester.Rule
  minor version: 0
  major version: 59
  flags: flags: (0x0021) ACC_PUBLIC, ACC_SUPER
  this_class: org.apache.catalina.startup.AddPortOffsetRule
  super_class: org.apache.tomcat.util.digester.Rule
{
  public void <init>();
    descriptor: ()V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // org.apache.catalina.startup.AddPortOffsetRule this
         0: .line 24
            aload 0 /* this */
            invokespecial org.apache.tomcat.util.digester.Rule.<init>:()V
            return
        end local 0 // org.apache.catalina.startup.AddPortOffsetRule this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lorg/apache/catalina/startup/AddPortOffsetRule;

  public void begin(java.lang.String, java.lang.String, org.xml.sax.Attributes);
    descriptor: (Ljava/lang/String;Ljava/lang/String;Lorg/xml/sax/Attributes;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=8, args_size=4
        start local 0 // org.apache.catalina.startup.AddPortOffsetRule this
        start local 1 // java.lang.String namespace
        start local 2 // java.lang.String name
        start local 3 // org.xml.sax.Attributes attributes
         0: .line 30
            aload 0 /* this */
            getfield org.apache.catalina.startup.AddPortOffsetRule.digester:Lorg/apache/tomcat/util/digester/Digester;
            invokevirtual org.apache.tomcat.util.digester.Digester.peek:()Ljava/lang/Object;
            checkcast org.apache.catalina.connector.Connector
            astore 4 /* conn */
        start local 4 // org.apache.catalina.connector.Connector conn
         1: .line 31
            aload 0 /* this */
            getfield org.apache.catalina.startup.AddPortOffsetRule.digester:Lorg/apache/tomcat/util/digester/Digester;
            iconst_2
            invokevirtual org.apache.tomcat.util.digester.Digester.peek:(I)Ljava/lang/Object;
            checkcast org.apache.catalina.Server
            astore 5 /* server */
        start local 5 // org.apache.catalina.Server server
         2: .line 33
            aload 5 /* server */
            invokeinterface org.apache.catalina.Server.getPortOffset:()I
            istore 6 /* portOffset */
        start local 6 // int portOffset
         3: .line 34
            aload 4 /* conn */
            iload 6 /* portOffset */
            invokevirtual org.apache.catalina.connector.Connector.setPortOffset:(I)V
         4: .line 36
            aload 0 /* this */
            getfield org.apache.catalina.startup.AddPortOffsetRule.digester:Lorg/apache/tomcat/util/digester/Digester;
            invokevirtual org.apache.tomcat.util.digester.Digester.getGeneratedCode:()Ljava/lang/StringBuilder;
            astore 7 /* code */
        start local 7 // java.lang.StringBuilder code
         5: .line 37
            aload 7 /* code */
            ifnull 9
         6: .line 38
            aload 7 /* code */
            aload 0 /* this */
            getfield org.apache.catalina.startup.AddPortOffsetRule.digester:Lorg/apache/tomcat/util/digester/Digester;
            aload 4 /* conn */
            invokevirtual org.apache.tomcat.util.digester.Digester.toVariableName:(Ljava/lang/Object;)Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            ldc ".setPortOffset("
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            pop
         7: .line 39
            aload 7 /* code */
            aload 0 /* this */
            getfield org.apache.catalina.startup.AddPortOffsetRule.digester:Lorg/apache/tomcat/util/digester/Digester;
            aload 5 /* server */
            invokevirtual org.apache.tomcat.util.digester.Digester.toVariableName:(Ljava/lang/Object;)Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            ldc ".getPortOffset());"
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            pop
         8: .line 40
            aload 7 /* code */
            invokestatic java.lang.System.lineSeparator:()Ljava/lang/String;
            invokevirtual java.lang.StringBuilder.append:(Ljava/lang/String;)Ljava/lang/StringBuilder;
            pop
         9: .line 42
      StackMap locals: org.apache.catalina.startup.AddPortOffsetRule java.lang.String java.lang.String org.xml.sax.Attributes org.apache.catalina.connector.Connector org.apache.catalina.Server int java.lang.StringBuilder
      StackMap stack:
            return
        end local 7 // java.lang.StringBuilder code
        end local 6 // int portOffset
        end local 5 // org.apache.catalina.Server server
        end local 4 // org.apache.catalina.connector.Connector conn
        end local 3 // org.xml.sax.Attributes attributes
        end local 2 // java.lang.String name
        end local 1 // java.lang.String namespace
        end local 0 // org.apache.catalina.startup.AddPortOffsetRule this
      LocalVariableTable:
        Start  End  Slot        Name  Signature
            0   10     0        this  Lorg/apache/catalina/startup/AddPortOffsetRule;
            0   10     1   namespace  Ljava/lang/String;
            0   10     2        name  Ljava/lang/String;
            0   10     3  attributes  Lorg/xml/sax/Attributes;
            1   10     4        conn  Lorg/apache/catalina/connector/Connector;
            2   10     5      server  Lorg/apache/catalina/Server;
            3   10     6  portOffset  I
            5   10     7        code  Ljava/lang/StringBuilder;
    Exceptions:
      throws java.lang.Exception
    MethodParameters:
            Name  Flags
      namespace   
      name        
      attributes  
}
SourceFile: "AddPortOffsetRule.java"