Claus Ibsen created CAMEL-23870:
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Summary: Add HeapHistogram dev console and TUI panel for
class-level memory analysis
Key: CAMEL-23870
URL: https://issues.apache.org/jira/browse/CAMEL-23870
Project: Camel
Issue Type: Improvement
Components: camel-jbang, camel-core
Reporter: Claus Ibsen
Add a new dev console that exposes a JVM class histogram from the running Camel
application, and a corresponding TUI panel to visualize it.
h3. Dev Console: HeapHistogramDevConsole
A new dev console (e.g. jvm/heap-histogram) that uses DiagnosticCommandMBean to
invoke gcClassHistogram inside the running JVM:
{code:java}
MBeanServer server = ManagementFactory.getPlatformMBeanServer();
ObjectName name = new ObjectName("com.sun.management:type=DiagnosticCommand");
String histogram = (String) server.invoke(name, "gcClassHistogram",
new Object[]{null}, new String[]{"[Ljava.lang.String;"});
{code}
This returns the same output as {{jcmd <pid> GC.class_histogram}} but runs
inside the target JVM through the dev console - no external jcmd access needed.
This fits the existing pattern used by MemoryDevConsole and JvmDevConsole.
The JSON response should include:
* Array of class entries: class name, instance count, total bytes
* Top N classes by default (e.g. top 50) to keep response size manageable
* Option to trigger a full GC before collecting (live objects only)
* Summary totals
h3. TUI Panel
A new tab (accessible via More menu) showing the class histogram as a sortable
table:
* Columns: class name, instance count, total bytes
* Sortable by any column (default: bytes descending)
* Search/filter support
* Complements the existing Memory tab which shows aggregate heap/GC stats but
not what is consuming the heap
h3. Use Case
When investigating memory issues in a running Camel integration, users
currently see heap totals in the Memory tab but cannot determine *what* is
consuming the heap without attaching an external tool like VisualVM or MAT. The
class histogram gives immediate visibility into the largest consumers directly
from the TUI.
h3. Reference
The boot-ui project (https://github.com/jdubois/boot-ui) has a similar Heap
Dump panel that captures and analyzes heap dumps showing class histograms
(names and sizes only, never object values).
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