issue 34046 velocity memory & sync issues

[wezell]

Summary

Reduces memory allocations and fixes synchronization issues in Velocity page rendering.

Memory Optimizations

• ThreadLocal pools for StringBuilder, StringWriter, and arrays in hot paths
• byte[] page cache instead of String to eliminate encoding roundtrips
• Singleton viewtools to avoid repeated instantiation
• Capacity-limited buffers to cap memory usage per thread

Sync Fixes

• Striped locks with timeout in DotResourceLoader to prevent thundering herd
• Avoid unnecessary session attribute writes that caused contention

Other

• Fixed NPE in LanguageWebAPIImpl
• Improved DotConcurrentFactoryTest runtime (~3s vs ~60-90s)

Files Changed

Area	Key Files
Velocity Core	VelocityUtil, VelocityLiveMode, DotResourceLoader, PageRenderUtil
Caching	StaticPageCache, PageCacheParameters
Content	ContentMap, StringifyObject
Filters	CMSFilter, CMSUrlUtil, LanguageWebAPIImpl
Velocity Parser	ASTMethod

Impact: ~90% reduction in temporary allocations for typical page renders.

Conversation link

https://dotcms.slack.com/archives/C04FRV45YR5/p1765222245235399

[wezell]

Sped up DotConcurrentFactoryTest

Key Optimizations

1. Reduced sleep in PrintTask: 500ms → 20ms
2. Reduced sleep in ConditionalSubmitter test: 8 seconds → 200ms
3. Reduced iteration counts: Only as many as needed to verify behavior
4. Eliminated busy-wait polling loops: Replaced with Future.get() awaits
5. Used proper assertions: assertSame/assertNotSame instead of assertTrue/assertFalse
6. Added proper shutdown: ExecutorService cleanup

Estimated Time Savings

Before	After
~60-90 seconds	~2-3 seconds