The best way to analyze the HTTP traffic sent by my java code?

I have some new Java code (using Apache commons HTTP Library) and old (strictly using java 1.4 API), and try to rewrite the old code with the newer Apache commons library However, it doesn't work, and I'm trying to find out why The request is being sent, but my new code timed out on the receiving server I can't access Because the old code was valid, I had to screw up the HTTP request It is very useful to use some kind of HTTP traffic sniffer to check the content sent so that I can see the differences between them

I downloaded some HTTP sniffers (this one and that one) from the Internet, but none of them captured any HTTP data sent by my java code (but they really worked when I sent random requests from the browser) Any ideas on how I can master these data?

Solution

Use Wireshark

It's great, free, open source, cross platform, and can highlight different network layers, and it doesn't run from suspicious websites that look like SEO spam

Snort is another good, but it is more suitable for intrusion detection and automatic response However, it has a great sniffer