[java] Auto EP and compile model support (microsoft#25131)

### Description
Java API for compile model and EP discovery APIs. Roughly equivalent to
the C# version in microsoft#24604.

cc: @skottmckay.

I haven't quite got the CMake configured so the Java tests for the ep
registration only run when the ONNX Runtime shared provider support is
built, but everything else works. I expect that to be a quick fix, but
I'm not sure in what conditions it should be built and how we should
handle it so I don't know where/when to plumb it through.

### Motivation and Context
API parity for Java.

Author: Craigacp

cmake/onnxruntime_java.cmake

@@ -159,7 +159,7 @@ if (WIN32)
   if(NOT onnxruntime_ENABLE_STATIC_ANALYSIS)
     add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:onnxruntime> ${JAVA_PACKAGE_LIB_DIR}/$<TARGET_FILE_NAME:onnxruntime>)
     add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:onnxruntime4j_jni> ${JAVA_PACKAGE_JNI_DIR}/$<TARGET_FILE_NAME:onnxruntime4j_jni>)
-    if (onnxruntime_USE_CUDA OR onnxruntime_USE_DNNL OR onnxruntime_USE_OPENVINO OR onnxruntime_USE_TENSORRT OR (onnxruntime_USE_QNN AND NOT onnxruntime_BUILD_QNN_EP_STATIC_LIB))
+    if (TARGET onnxruntime_providers_shared)
       add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:onnxruntime_providers_shared> ${JAVA_PACKAGE_LIB_DIR}/$<TARGET_FILE_NAME:onnxruntime_providers_shared>)
     endif()
     if (onnxruntime_USE_CUDA)
@@ -207,7 +207,7 @@ if (WIN32)
 else()
   add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:onnxruntime> ${JAVA_PACKAGE_LIB_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime>)
   add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:onnxruntime4j_jni> ${JAVA_PACKAGE_JNI_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime4j_jni>)
-  if (onnxruntime_USE_CUDA OR onnxruntime_USE_DNNL OR onnxruntime_USE_OPENVINO OR onnxruntime_USE_TENSORRT OR (onnxruntime_USE_QNN AND NOT onnxruntime_BUILD_QNN_EP_STATIC_LIB))
+  if (TARGET onnxruntime_providers_shared)
     add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:onnxruntime_providers_shared> ${JAVA_PACKAGE_LIB_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime_providers_shared>)
   endif()
   if (onnxruntime_USE_CUDA)

cmake/onnxruntime_unittests.cmake

@@ -1640,6 +1640,10 @@ if (NOT CMAKE_SYSTEM_NAME STREQUAL "Emscripten")
           add_custom_command(TARGET onnxruntime_providers_qnn POST_BUILD
               COMMAND ${CMAKE_COMMAND} -E copy ${QNN_LIB_FILES} ${JAVA_NATIVE_TEST_DIR})
         endif()
+	if (WIN32)
+          set(EXAMPLE_PLUGIN_EP_DST_FILE_NAME $<IF:$<BOOL:${WIN32}>,$<TARGET_FILE_NAME:example_plugin_ep>,$<TARGET_LINKER_FILE_NAME:example_plugin_ep>>)
+          add_custom_command(TARGET custom_op_library POST_BUILD COMMAND ${CMAKE_COMMAND} -E copy_if_different $<TARGET_FILE:example_plugin_ep> ${JAVA_NATIVE_TEST_DIR}/${EXAMPLE_PLUGIN_EP_DST_FILE_NAME})
+	endif()
 
         # delegate to gradle's test runner
 

java/src/main/java/ai/onnxruntime/OnnxRuntime.java

@@ -42,6 +42,8 @@ final class OnnxRuntime {
   private static final int ORT_API_VERSION_13 = 13;
   // Post 1.13 builds of the ORT API
   private static final int ORT_API_VERSION_14 = 14;
+  // Post 1.22 builds of the ORT API
+  private static final int ORT_API_VERSION_23 = 23;
 
   // The initial release of the ORT training API.
   private static final int ORT_TRAINING_API_VERSION_1 = 1;
@@ -103,6 +105,9 @@ final class OnnxRuntime {
   /** The Training API handle. */
   static long ortTrainingApiHandle;
 
+  /** The Compile API handle. */
+  static long ortCompileApiHandle;
+
   /** Is training enabled in the native library */
   static boolean trainingEnabled;
 
@@ -176,12 +181,13 @@ static synchronized void init() throws IOException {
       }
       load(ONNXRUNTIME_JNI_LIBRARY_NAME);
 
-      ortApiHandle = initialiseAPIBase(ORT_API_VERSION_14);
+      ortApiHandle = initialiseAPIBase(ORT_API_VERSION_23);
       if (ortApiHandle == 0L) {
         throw new IllegalStateException(
             "There is a mismatch between the ORT class files and the ORT native library, and the native library could not be loaded");
       }
-      ortTrainingApiHandle = initialiseTrainingAPIBase(ortApiHandle, ORT_API_VERSION_14);
+      ortTrainingApiHandle = initialiseTrainingAPIBase(ortApiHandle, ORT_API_VERSION_23);
+      ortCompileApiHandle = initialiseCompileAPIBase(ortApiHandle);
       trainingEnabled = ortTrainingApiHandle != 0L;
       providers = initialiseProviders(ortApiHandle);
       version = initialiseVersion();
@@ -499,6 +505,14 @@ private static EnumSet<OrtProvider> initialiseProviders(long ortApiHandle) {
    */
   private static native long initialiseTrainingAPIBase(long apiHandle, int apiVersionNumber);
 
+  /**
+   * Get a reference to the compile API struct.
+   *
+   * @param apiHandle The ORT API struct pointer.
+   * @return A pointer to the compile API struct.
+   */
+  private static native long initialiseCompileAPIBase(long apiHandle);
+
   /**
    * Gets the array of available providers.
    *

java/src/main/java/ai/onnxruntime/OrtEnvironment.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2019, 2024 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2019, 2025 Oracle and/or its affiliates. All rights reserved.
  * Licensed under the MIT License.
  */
 package ai.onnxruntime;
@@ -8,7 +8,11 @@
 import ai.onnxruntime.OrtTrainingSession.OrtCheckpointState;
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.Collections;
 import java.util.EnumSet;
+import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.logging.Logger;
 
@@ -442,6 +446,48 @@ public static EnumSet<OrtProvider> getAvailableProviders() {
     return OnnxRuntime.providers.clone();
   }
 
+  /**
+   * Registers an execution provider library with this OrtEnvironment.
+   *
+   * @param registrationName The name to register the library with (used to remove it later with
+   *     {@link #unregisterExecutionProviderLibrary(String)}).
+   * @param libraryPath The path to the library binary on disk.
+   * @throws OrtException If the library could not be registered.
+   */
+  public void registerExecutionProviderLibrary(String registrationName, String libraryPath)
+      throws OrtException {
+    registerExecutionProviderLibrary(
+        OnnxRuntime.ortApiHandle, nativeHandle, registrationName, libraryPath);
+  }
+
+  /**
+   * Unregisters an execution provider library from this OrtEnvironment.
+   *
+   * @param registrationName The name the library was registered under.
+   * @throws OrtException If the library could not be removed.
+   */
+  public void unregisterExecutionProviderLibrary(String registrationName) throws OrtException {
+    unregisterExecutionProviderLibrary(OnnxRuntime.ortApiHandle, nativeHandle, registrationName);
+  }
+
+  /**
+   * Get the list of all execution provider and device combinations that are available.
+   *
+   * @see OrtSession.SessionOptions#addExecutionProvider(List, Map)
+   * @return The list of execution provider and device combinations.
+   * @throws OrtException If the devices could not be listed.
+   */
+  public List<OrtEpDevice> getEpDevices() throws OrtException {
+    long[] deviceHandles = getEpDevices(OnnxRuntime.ortApiHandle, nativeHandle);
+
+    List<OrtEpDevice> devicesList = new ArrayList<>();
+    for (long deviceHandle : deviceHandles) {
+      devicesList.add(new OrtEpDevice(deviceHandle));
+    }
+
+    return Collections.unmodifiableList(devicesList);
+  }
+
   /**
    * Creates the native object.
    *
@@ -476,6 +522,40 @@ private static native long createHandle(
    */
   private static native long getDefaultAllocator(long apiHandle) throws OrtException;
 
+  /**
+   * Registers the specified execution provider with this OrtEnvironment.
+   *
+   * @param apiHandle The API handle.
+   * @param nativeHandle The OrtEnvironment handle.
+   * @param registrationName The name of the execution provider.
+   * @param libraryPath The path to the execution provider binary.
+   * @throws OrtException If the registration failed.
+   */
+  private static native void registerExecutionProviderLibrary(
+      long apiHandle, long nativeHandle, String registrationName, String libraryPath)
+      throws OrtException;
+
+  /**
+   * Removes the specified execution provider from this OrtEnvironment.
+   *
+   * @param apiHandle The API handle.
+   * @param nativeHandle The OrtEnvironment handle.
+   * @param registrationName The name of the execution provider.
+   * @throws OrtException If the removal failed.
+   */
+  private static native void unregisterExecutionProviderLibrary(
+      long apiHandle, long nativeHandle, String registrationName) throws OrtException;
+
+  /**
+   * Gets handles for the EP device tuples available in this OrtEnvironment.
+   *
+   * @param apiHandle The API handle to use.
+   * @param nativeHandle The OrtEnvironment handle.
+   * @return An array of OrtEpDevice handles.
+   * @throws OrtException If the call failed.
+   */
+  private static native long[] getEpDevices(long apiHandle, long nativeHandle) throws OrtException;
+
   /**
    * Closes the OrtEnvironment, frees the handle.
    *

java/src/main/java/ai/onnxruntime/OrtEpDevice.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * Licensed under the MIT License.
+ */
+package ai.onnxruntime;
+
+import java.util.Map;
+
+/** A tuple of Execution Provider information and the hardware device. */
+public final class OrtEpDevice {
+
+  private final long nativeHandle;
+
+  private final String epName;
+  private final String epVendor;
+  private final Map<String, String> epMetadata;
+  private final Map<String, String> epOptions;
+  private final OrtHardwareDevice device;
+
+  /**
+   * Construct an OrtEpDevice tuple from the native pointer.
+   *
+   * @param nativeHandle The native pointer.
+   */
+  OrtEpDevice(long nativeHandle) {
+    this.nativeHandle = nativeHandle;
+    this.epName = getName(OnnxRuntime.ortApiHandle, nativeHandle);
+    this.epVendor = getVendor(OnnxRuntime.ortApiHandle, nativeHandle);
+    String[][] metadata = getMetadata(OnnxRuntime.ortApiHandle, nativeHandle);
+    this.epMetadata = OrtUtil.convertToMap(metadata);
+    String[][] options = getOptions(OnnxRuntime.ortApiHandle, nativeHandle);
+    this.epOptions = OrtUtil.convertToMap(options);
+    this.device = new OrtHardwareDevice(getDeviceHandle(OnnxRuntime.ortApiHandle, nativeHandle));
+  }
+
+  /**
+   * Return the native pointer.
+   *
+   * @return The native pointer.
+   */
+  long getNativeHandle() {
+    return nativeHandle;
+  }
+
+  /**
+   * Gets the EP name.
+   *
+   * @return The EP name.
+   */
+  public String getName() {
+    return epName;
+  }
+
+  /**
+   * Gets the vendor name.
+   *
+   * @return The vendor name.
+   */
+  public String getVendor() {
+    return epVendor;
+  }
+
+  /**
+   * Gets an unmodifiable view on the EP metadata.
+   *
+   * @return The EP metadata.
+   */
+  public Map<String, String> getMetadata() {
+    return epMetadata;
+  }
+
+  /**
+   * Gets an unmodifiable view on the EP options.
+   *
+   * @return The EP options.
+   */
+  public Map<String, String> getOptions() {
+    return epOptions;
+  }
+
+  /**
+   * Gets the device information.
+   *
+   * @return The device information.
+   */
+  public OrtHardwareDevice getDevice() {
+    return device;
+  }
+
+  @Override
+  public String toString() {
+    return "OrtEpDevice{"
+        + "epName='"
+        + epName
+        + '\''
+        + ", epVendor='"
+        + epVendor
+        + '\''
+        + ", epMetadata="
+        + epMetadata
+        + ", epOptions="
+        + epOptions
+        + ", device="
+        + device
+        + '}';
+  }
+
+  private static native String getName(long apiHandle, long nativeHandle);
+
+  private static native String getVendor(long apiHandle, long nativeHandle);
+
+  private static native String[][] getMetadata(long apiHandle, long nativeHandle);
+
+  private static native String[][] getOptions(long apiHandle, long nativeHandle);
+
+  private static native long getDeviceHandle(long apiHandle, long nativeHandle);
+}

java/src/main/java/ai/onnxruntime/providers/OrtFlags.java renamed to java/src/main/java/ai/onnxruntime/OrtFlags.java

@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
  * Licensed under the MIT License.
  */
-package ai.onnxruntime.providers;
+package ai.onnxruntime;
 
 import java.util.EnumSet;