Java SDK: Add TCP/TLS integration tests and examples

[mmodzelewski]

Summary

The Java SDK has TCP/TLS support implemented (both blocking via IggyTcpClientBuilder.enableTls() and async via Netty's SslContextBuilder), but there are no dedicated integration tests that actually connect to a TLS-enabled server, and no TLS examples in examples/java/.

Current State

• TLS implementation: Present in both blocking (IggyTcpClient) and async (AsyncTcpConnection) clients
• Existing tests: AsyncIggyTcpClientBuilderTest has unit-level tests for TLS builder methods (testBuildClientWithTlsBoolean, testBuildClientWithEnableTls, testHandleNullTlsCertificateString), but none actually connect to a TLS-enabled server
• Examples: No TLS-specific examples exist in examples/java/

Requirements

Integration Tests

• Add integration test(s) that start an Iggy server with TLS enabled and connect using the Java TCP client with TLS
• Test both blocking and async TLS connections
• Use custom certificates from core/certs/ (iggy_ca_cert.pem, iggy_cert.pem, iggy_key.pem)
• Test scenarios:
  • Successful TLS connection with custom CA certificate
  • Successful TLS connection with server certificate
  • Connection failure when TLS is required but client doesn't use TLS
  • Basic message send/receive over TLS connection
• Reference the C# TLS integration tests (foreign/csharp/Iggy_SDK.Tests.Integration/IggyTlsConnectionTests.cs) as an example of the approach

Examples

• Add a TLS example in examples/java/ demonstrating:
  • How to configure the client builder with TLS enabled
  • How to specify a custom CA certificate file
  • A simple producer/consumer flow over TLS

Reference

• Server TLS config env vars: IGGY_TCP_TLS_ENABLED=true, IGGY_TCP_TLS_CERT_FILE, IGGY_TCP_TLS_KEY_FILE
• Custom certs location: core/certs/
• C# TLS tests for reference: foreign/csharp/Iggy_SDK.Tests.Integration/IggyTlsConnectionTests.cs

[atharvalade]

I'd like to work on this issue.