public static void main(String[] args) {
        try {
            ProcessBuilder pb =
                    new ProcessBuilder("cmd.exe", "/C", "javap", "-verbose", "<path_to_class_file>");
            Map<String, String> env = pb.environment();
            env.put("Path", "C:\Program Files\Java\jdk-11.0.1\bin");
            Process p = pb.start();
            BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream()));
            String line = "";
            while ((line = br.readLine()) != null) {
                System.out.println(line);
            }
            int exitValue = p.waitFor();
            System.out.println("nnExit Value is " + exitValue);
        } catch (InterruptedException | IOException e) {
            e.printStackTrace();
        }
    }

Classfile /D:/HelloWorld.class
     Last modified 21-Feb-2019; size 425 bytes
     MD5 checksum 29fe59b7ca108f7691a1f144ccd37c90
     Compiled from "HelloWorld.java"
    public class HelloWorld
     minor version: 0
     major version: 55
     ...
    public HelloWorld();
       descriptor: ()V
       flags: (0x0001) ACC_PUBLIC
    Code:
      stack=1, locals=1, args_size=1
         0: aload_0
         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
         4: return