Why Do Top-Level Swing Containers Persist After `dispose()` and `gc()`?

Removing Top-Level Containers During Runtime

When attempting to remove top-level containers at runtime, developers often encounter the "swing nightmare" of persistent containers despite using methods like dispose() and gc().

Understanding the Process

To successfully remove top-level containers, it's crucial to understand that dispose() merely requests the release of resources allocated to the container's heavyweight peer. However, this release only occurs after the WINDOW_CLOSING event has been processed on the EventQueue.

Furthermore, invoking gc() does not guarantee immediate memory reclamation; it merely suggests that the garbage collector should consider it.

Causes of the "Swing Nightmare"

The "swing nightmare" occurs because even after triggering dispose(), the container's peer remains alive until the WINDOW_CLOSING event is processed. This hampers memory reclamation efforts, and if multiple containers are created and disposed of in succession, it can lead to a cascade of unclosed resources.

Overcoming the Nightmare

Two approaches can effectively address this issue:

• Emergent: Create new VMs for each iteration, thereby resetting memory consumption.
• Urgent: Eliminate heavyweight components by going headless and rendering graphics using lightweight components only.

Additional Insights

Profiling techniques can provide valuable insights into the memory consumption issue. Tools like jvisualvm can reveal that periodic collection struggles to return to baseline, indicating lingering resources.

The above is the detailed content of Why Do Top-Level Swing Containers Persist After `dispose()` and `gc()`?. For more information, please follow other related articles on the PHP Chinese website!