Move columnar runtime config helpers to Java

[gerashegalov]

Related to #14834.

Description

This PR is one reviewable layer in the unshim stack introduced by #15025. It moves columnar runtime configuration helpers into Java-friendly sources so runtime configuration access can be shared by later caller-migration layers.

Stack context

• Stack introduction: Add default common unshim packaging flow #15025
• Previous layer: Move columnar scalar utilities to Java modules #15044
• Next layer: Move columnar table value helpers to Java modules #15045

Testing and validation notes

• No standalone behavior change is intended in this layer. It is covered by the full-stack packaging/build validation described in Add default common unshim packaging flow #15025 and the existing tests for the affected subsystem.
• The full split stack was verified to be tree-equivalent to the pre-split stack top.

Checklists

Documentation

• Updated for new or modified user-facing features or behaviors
• No user-facing change

Testing

• Added or modified tests to cover new code paths
• Covered by existing tests
  (Covered by the validation notes in the PR description.)
• Not required

Performance

• Tests ran and results are added in the PR description
• Issue filed with a link in the PR description
• Not required

[greptile-apps]

Greptile Summary

This PR migrates a set of columnar runtime-configuration helpers from Scala (sql-plugin) into Java (sql-plugin-columnar) to enable downstream Scala-free callers in the unshim stack. Call-sites in GpuReaderFactory.scala and WithRetrySuite.scala are updated to use Java constructors instead of the Scala companion-object apply methods.

• Eight new Java classes are added (AutoCloseableTargetSize, CombineConf, DefaultThreadPoolConf, MemoryBoundedPoolConf, ThreadPoolConf, HostAllocResult, ExecutorCache, GpuOrcTimezoneUtils, DeviceBuffersUtils), faithfully porting the Scala originals with initialization-on-demand holders replacing lazy val.
• Two Scala source files (ExecutorCache.scala, GpuOrcTimezoneUtils.scala) are deleted; four test call-sites and one Iceberg call-site are trivially updated.

Confidence Score: 4/5

The change is a straightforward Scala-to-Java translation with no intended behavior change; nearly all of it is safe, with one native-resource cleanup inconsistency in GpuOrcTimezoneUtils.java worth fixing before merge.

The closeAll(ColumnView[]) method in GpuOrcTimezoneUtils.java does not catch exceptions thrown by individual close() calls, so a single failing close leaves the remaining GPU columns in the array unclosed. This is inconsistent with both the closeAll(List<ColumnView>) overload in the same file and DeviceBuffersUtils.closeAll, and the array version is called from the finally path that releases all output columns.

sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/GpuOrcTimezoneUtils.java — the closeAll(ColumnView[]) method needs exception-safe iteration before merge.

Important Files Changed

Filename	Overview
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/GpuOrcTimezoneUtils.java	Port of GpuOrcTimezoneUtils from Scala to Java; contains an inconsistency in closeAll(ColumnView[]) that can leak GPU column references if any close() call throws.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/DeviceBuffersUtils.java	New Java utility for device buffer allocation and ref-count management; exception-safe with proper suppressed-exception chaining in closeAll.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/AutoCloseableTargetSize.java	Java port of the Scala case class; exposes both public final fields and no-arg accessor methods for Java/Scala interop; no-op close() and serialization are intentional.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/ExecutorCache.java	Correct translation of Scala lazy vals to the initialization-on-demand holder idiom; package-private visibility matches original private[rapids] scope.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/CombineConf.java	Clean Scala case class to Java value class port; Serializable with explicit serialVersionUID, proper equals/hashCode.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/ThreadPoolConf.java	New Java interface extending Serializable; simple and correct.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/DefaultThreadPoolConf.java	New Java implementation of ThreadPoolConf; correct serialVersionUID and equals/hashCode.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/MemoryBoundedPoolConf.java	New Java implementation of ThreadPoolConf with memory-bounded extensions; clean translation.
sql-plugin-columnar/src/main/java/com/nvidia/spark/rapids/HostAllocResult.java	Straightforward Java value class holding a HostMemoryBuffer and pinned flag; no resource management concerns (caller owns the buffer).
iceberg/common/src/main/scala/org/apache/iceberg/spark/source/GpuReaderFactory.scala	Trivial call-site update: CombineConf case-class apply → new CombineConf(...) Java constructor now that the class lives in Java.
tests/src/test/scala/com/nvidia/spark/rapids/WithRetrySuite.scala	Four test call-sites updated from Scala apply to new Java constructor for AutoCloseableTargetSize; no logic change.
sql-plugin/src/main/scala/com/nvidia/spark/rapids/ExecutorCache.scala	Deleted; functionality moved to ExecutorCache.java.
sql-plugin/src/main/scala/com/nvidia/spark/rapids/GpuOrcTimezoneUtils.scala	Deleted; functionality moved to GpuOrcTimezoneUtils.java.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    subgraph Before
        ScalaEC[ExecutorCache.scala\nlazy val]
        ScalaORC[GpuOrcTimezoneUtils.scala\nScala object]
        ScalaCC[CombineConf / AutoCloseableTargetSize\nScala case classes in sql-plugin]
    end

    subgraph After["After (sql-plugin-columnar Java)"]
        JavaEC[ExecutorCache.java\nInit-on-demand holders]
        JavaORC[GpuOrcTimezoneUtils.java\nfinal utility class]
        JavaCC[CombineConf / AutoCloseableTargetSize\nJava value classes]
        JavaTP[ThreadPoolConf interface\nDefaultThreadPoolConf / MemoryBoundedPoolConf]
        JavaDB[DeviceBuffersUtils.java]
        JavaHA[HostAllocResult.java]
    end

    ScalaEC -->|deleted / replaced by| JavaEC
    ScalaORC -->|deleted / replaced by| JavaORC
    ScalaCC -->|deleted / replaced by| JavaCC

    GpuReaderFactory[GpuReaderFactory.scala\niceberg] -->|new CombineConf| JavaCC
    WithRetrySuite[WithRetrySuite.scala\ntests] -->|new AutoCloseableTargetSize| JavaCC

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[greptile-apps]

The closeAll(ColumnView[]) overload does not guard against exceptions thrown by view.close(). If element i throws, elements i+1 through the end of newColumns are never closed, leaking native GPU memory. The companion closeAll(List<ColumnView>) in the same file and DeviceBuffersUtils.closeAll both handle this correctly by catching each element's exception individually.

Suggested change

	private static void closeAll(ColumnView[] views) {
	for (ColumnView view : views) {
	if (view != null) {
	view.close();
	}
	}
	}
	private static void closeAll(ColumnView[] views) {
	RuntimeException firstException = null;
	for (ColumnView view : views) {
	if (view != null) {
	try {
	view.close();
	} catch (RuntimeException e) {
	if (firstException == null) {
	firstException = e;
	} else {
	firstException.addSuppressed(e);
	}
	}
	}
	}
	if (firstException != null) {
	throw firstException;
	}
	}