BreakTest 2026.07.03

BreakTest 2026.07.03 Release Notes

BreakTest 2026.07.03 is the first public BreakTest release: an independent,
Apache-2.0, JMeter-compatible continuation focused on a leaner runtime, modern
HTTP, better debugging, and a smoother path from local scripts to scaled
execution.

BreakTest keeps the useful JMeter test-plan model and JMX workflow, while
moving the engine toward Java 21+, HTTP/2, lower resource usage, visual
diagnostics, AI-assisted repair workflows, and BreakTest Enterprise scale.

Highlights

• Modern HTTP path based on Apache HttpClient 5 with first-class HTTP/2 support.
• Lower memory and CPU pressure through lazy decompression, retention modes,
  lightweight cloning, lazy diagnostics, and allocation reductions.
• Java 21+ baseline with virtual-thread support.
• Parallel Controller and Fork Controller for realistic concurrency and
  independent branches of work.
• Unified Thread Group scheduling with closed/open workload models, phases,
  open-model helpers, pacing, and pause/resume support.
• Undo/redo support for common GUI test-plan edits.
• Background JMX loading and safe missing-plugin placeholders.
• Richer View Results Tree diagnostics, source navigation, and HAR-backed
  recorded-vs-replayed request/response diff views.
• Easier If/While conditions, transaction timing controls, random CSV ordering,
  CSV preview, and extractor fail-on-no-match options.
• Apache License 2.0, with Apache JMeter attribution retained.

Modern HTTP Runtime

• Added Apache HttpClient 5 sampler support for HTTP/1.1.
• Added an async HttpClient 5 HTTP/2 sampler path with HTTP/2 and HTTP/2
  preferred protocol selection.
• Added negotiated fallback, connect-time reporting, HTTP/2 upload content
  length handling, and safer HTTP/2 replay behavior.
• Reduced HTTP/2 resource usage by limiting reactor threads by default and
  avoiding unnecessary async client/reactor rebuilds between same-user
  iterations.
• Added conservative HTTP/2 closed-session retry handling for common HC5
  connection-closure failures.
• Fixed NTLM authentication on the HttpClient 5 path, including variable
  resolution before async auth callbacks.
• Kept HttpClient 4 runtime jars available for legacy plugin compatibility while
  keeping the built-in HTTP Request sampler on HttpClient 5.
• Added Brotli and Zstandard response decoding alongside gzip and deflate.

Resource Usage Improvements

• Lazy response decompression stores compressed bytes and decompresses only when
  response data is accessed.
• Response-processing modes can store compressed data, discard successful
  bodies, keep only failing bodies, or retain MD5 checksums.
• Lightweight test-plan cloning shares safe property state where possible and
  reduces per-thread object churn.
• Header merging, temporary property handling, and response read buffers were
  optimized for hot-path sampler execution.
• Rich SampleResult metadata is now lazy and listener-driven, avoiding
  unnecessary per-sample storage when diagnostics are not needed.
• A throughput regression in temporary property recovery was fixed while keeping
  the correctness improvements for identity semantics.

Controllers, Scheduling, And Flow Control

• Added native Parallel Controller execution with bounded parallel sampler
  scheduling and HTTP state safeguards.
• Added Fork Controller for asynchronous child branches that share virtual-user
  context and complete before thread teardown.
• Added unified Thread Group scheduling controls with closed/open model
  selection.
• Added open-model schedule helpers, even-arrival scheduling, max active thread
  limits, safe schedule parsing, and graph preview support.
• Added closed-model phases so a schedule can combine different ramp-up speeds,
  hold periods, and thread targets. This makes it possible to shape almost any
  closed workload model from one Thread Group schedule.
• Added Thread Group pacing controls.
• Cleared runtime user variables on new iterations when same-user mode is
  disabled, while preserving initial variables.
• Added Pause and Resume in the GUI and on the existing UDP command port, with
  bin/pause.* and bin/resume.* wrappers. Pausing is useful during ramp-up
  when you want to stop increasing load and hold the current point. In closed
  model, active threads stay active. In open model, new arrivals are paused and
  active threads finish naturally, so load drops while paused.
• Improved shutdown so it is quicker: shutdown no longer waits for timers to
  complete and only waits for in-flight server responses to finish cleanly.

GUI And Test-Plan Editing

• Added undo and redo for semantic tree edits including add, delete, update,
  move, and search/replace operations.
• Added background JMX loading with a loading overlay.
• Added opt-in fast GUI loading through jmeter.gui.load.fast=true.
• JMX files with missing plugin elements now load with disabled placeholders
  rather than failing the whole file.
• Added placeholder GUI panels and clear notifications for missing plugin
  elements.
• Improved Search Tree flagging for pre-processors, post-processors,
  assertions, timers, and config elements.
• Added selective "Remove Matching" for search results with confirmation so bulk
  cleanup can avoid deleting parent nodes accidentally.
• Improved GUI layout and editor resizing around controller panels and tree
  editors.

Scripting, Data, And Correlation

• Added structured If and While Controller condition rows with all/any matching,
  while preserving legacy condition expressions.
• Added loop/while index behavior options and exported index variable display.
• Added Transaction Controller measurement modes plus built-in delay and pacing
  controls.
• Added extractor fail-on-no-match options for Boundary, CSS/HTML, Regex,
  XPath, XPath2, JSONPath, and JMESPath extractors.
• Added random-order reading for CSV Data Set records.
• Added CSV preview of the first sample variable assignments.
• Focused scripting on JSR223/Groovy by removing legacy BeanShell, BSF/JEXL2,
  Rhino JavaScript, and LogKit paths.

Visual Debugging And HAR Migration

• View Results Tree now shows richer request/response diagnostics, endpoint
  details, HTTP/TLS metadata, cookies, variables, binary/text detection, and
  jump-to-source.
• Rendered response views and raw text response views now keep the expected
  response display lifecycle.
• BreakTest JMX metadata preserves origin and source-path information for
  debugging tools.
• HAR-backed recorded request/response tabs appear in View Results Tree and HTTP
  sampler editors when matching BreakTest HAR metadata is available.
• Recorded-vs-replayed diffs make HAR migration and HTTP/2 replay debugging
  easier.
• Transaction child samples preserve source test-element paths so folded
  transaction results can still navigate to the correct source element.
• HTTP/2 replay removes unsupported hop-by-hop headers and normalizes
  request/status lines for cleaner diffs.
• Host-only cookie matching is stricter so cookies do not leak to unrelated
  hosts or subdomains.

Compatibility Notes

• Existing JMeter JMX files remain supported where practical.
• Many package names, property names, command internals, and Maven coordinates
  intentionally still use jmeter or org.apache.jmeter for compatibility.
• BreakTest-specific JMX metadata may not round-trip into older JMeter versions.
• Plugins that depend on removed internals may need migration.
• Legacy HttpClient 4 jars are bundled for plugin compatibility, but the built-in
  HTTP Request sampler runs on HttpClient 5.
• RMI Remote Server style distributed execution is removed. Use BreakTest
  Enterprise or another controlled orchestration layer for distributed tests.
• Java 21 or later is required.

Security Notes

BreakTest inherits Apache JMeter's trusted-test-plan security model. Treat JMX
files as executable input: they can run scripts, load classes, read files, make
network requests, and interact with systems reachable from the runner.

Only open or run test plans you trust, or isolate them first. See
SECURITY.md and THREAT_MODEL.md for the
project security model and vulnerability reporting process.

Legal And Attribution

BreakTest is licensed under the Apache License, Version 2.0. BreakTest is a
derivative work of Apache JMeter, and Apache JMeter copyright and attribution
notices are retained in the source tree and distribution notices.

BreakTest is independent from The Apache Software Foundation. It is not
affiliated with, endorsed by, or sponsored by The Apache Software Foundation.