Package org.apache.tomcat.util.compat

## Class JreCompat

- java.lang.Object
- - org.apache.tomcat.util.compat.JreCompat

- Direct Known Subclasses:
    `Jre19Compat`

      public class JreCompat
      extends java.lang.Object

  This is the base implementation class for JRE compatibility and provides an implementation based on Java 7. Sub-classes may extend this class and provide alternative implementations for later JRE versions

- - ### Constructor Summary

    Constructors
    Constructor | Description
    --- | ---
    `JreCompat()` |

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method | Description
    --- | --- | ---
    `void` | `addBootModulePath​(java.util.Deque<java.net.URL> classPathUrlsToProcess)` | Obtains the URLs for all the JARs on the module path when the JVM starts and adds them to the provided Deque.
    `boolean` | `canAccess​(java.lang.Object base, java.lang.reflect.AccessibleObject accessibleObject)` | Is the accessibleObject accessible (as a result of appropriate module exports) on the provided instance?
    `java.lang.Object` | `createVirtualThreadBuilder​(java.lang.String name)` | Create a thread builder for virtual threads using the given name to name the threads.
    `void` | `disableCachingForJarUrlConnections()` | Disables caching for JAR URL connections.
    `java.lang.String` | `getApplicationProtocol​(javax.net.ssl.SSLEngine sslEngine)` | Get the application protocol that has been negotiated for connection associated with the given SSLEngine.
    `java.security.KeyStore.LoadStoreParameter` | `getDomainLoadStoreParameter​(java.net.URI uri)` |
    `java.lang.Object` | `getExecutor​(java.lang.Thread thread)` | Obtains the executor, if any, used to create the provided thread.
    `static JreCompat` | `getInstance()` |
    `java.lang.String` | `getModuleName​(java.lang.Class<?> type)` | What is the module of the given class?
    `static boolean` | `isAlpnSupported()` |
    `boolean` | `isExported​(java.lang.Class<?> type)` | Is the given class in an exported package?
    `boolean` | `isInstanceOfInaccessibleObjectException​(java.lang.Throwable t)` | Test if the provided exception is an instance of java.lang.reflect.InaccessibleObjectException.
    `static boolean` | `isJre11Available()` |
    `static boolean` | `isJre16Available()` |
    `static boolean` | `isJre19Available()` |
    `static boolean` | `isJre21Available()` |
    `static boolean` | `isJre8Available()` |
    `static boolean` | `isJre9Available()` |
    `boolean` | `jarFileIsMultiRelease​(java.util.jar.JarFile jarFile)` | Is this JarFile a multi-release JAR file.
    `java.util.jar.JarFile` | `jarFileNewInstance​(java.io.File f)` | Creates a new JarFile instance.
    `java.util.jar.JarFile` | `jarFileNewInstance​(java.lang.String s)` | Creates a new JarFile instance.
    `int` | `jarFileRuntimeMajorVersion()` |
    `void` | `setApplicationProtocols​(javax.net.ssl.SSLParameters sslParameters, java.lang.String[] protocols)` | Set the application protocols the server will accept for ALPN
    `void` | `setUseServerCipherSuitesOrder​(javax.net.ssl.SSLParameters engine, boolean useCipherSuitesOrder)` |
    `void` | `threadBuilderStart​(java.lang.Object threadBuilder, java.lang.Runnable command)` | Create a thread with the given thread builder and use it to execute the given runnable.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### JreCompat

          public JreCompat()

  - ### Method Detail

    - #### getInstance

          public static JreCompat getInstance()

    - #### isAlpnSupported

          public static boolean isAlpnSupported()

    - #### isJre8Available

          public static boolean isJre8Available()

    - #### isJre9Available

          public static boolean isJre9Available()

    - #### isJre11Available

          public static boolean isJre11Available()

    - #### isJre16Available

          public static boolean isJre16Available()

    - #### isJre19Available

          public static boolean isJre19Available()

    - #### isJre21Available

          public static boolean isJre21Available()

    - #### setUseServerCipherSuitesOrder

          public void setUseServerCipherSuitesOrder​(javax.net.ssl.SSLParameters engine,
                                                    boolean useCipherSuitesOrder)

    - #### getDomainLoadStoreParameter

          public java.security.KeyStore.LoadStoreParameter getDomainLoadStoreParameter​(java.net.URI uri)

    - #### isInstanceOfInaccessibleObjectException

          public boolean isInstanceOfInaccessibleObjectException​(java.lang.Throwable t)

      Test if the provided exception is an instance of java.lang.reflect.InaccessibleObjectException.
      Parameters:
        `t` - The exception to test
      Returns:
        `true` if the exception is an instance of InaccessibleObjectException, otherwise `false`

    - #### setApplicationProtocols

          public void setApplicationProtocols​(javax.net.ssl.SSLParameters sslParameters,
                                              java.lang.String[] protocols)

      Set the application protocols the server will accept for ALPN
      Parameters:
        `sslParameters` - The SSL parameters for a connection
        `protocols` - The application protocols to be allowed for that connection

    - #### getApplicationProtocol

          public java.lang.String getApplicationProtocol​(javax.net.ssl.SSLEngine sslEngine)

      Get the application protocol that has been negotiated for connection associated with the given SSLEngine.
      Parameters:
        `sslEngine` - The SSLEngine for which to obtain the negotiated protocol
      Returns:
        The name of the negotiated protocol

    - #### disableCachingForJarUrlConnections

          public void disableCachingForJarUrlConnections()
                                                  throws java.io.IOException

      Disables caching for JAR URL connections. For Java 8 and earlier, this also disables caching for ALL URL connections.
      Throws:
        `java.io.IOException` - If a dummy JAR URLConnection can not be created

    - #### addBootModulePath

          public void addBootModulePath​(java.util.Deque<java.net.URL> classPathUrlsToProcess)

      Obtains the URLs for all the JARs on the module path when the JVM starts and adds them to the provided Deque.
      Parameters:
        `classPathUrlsToProcess` - The Deque to which the modules should be added

    - #### jarFileNewInstance

          public final java.util.jar.JarFile jarFileNewInstance​(java.lang.String s)
                                                         throws java.io.IOException

      Creates a new JarFile instance. When running on Java 9 and later, the JarFile will be multi-release JAR aware. While this isn't strictly required to be in this package, it is provided as a convenience method.
      Parameters:
        `s` - The JAR file to open
      Returns:
        A JarFile instance based on the provided path
      Throws:
        `java.io.IOException` - If an I/O error occurs creating the JarFile instance

    - #### jarFileNewInstance

          public java.util.jar.JarFile jarFileNewInstance​(java.io.File f)
                                                   throws java.io.IOException

      Creates a new JarFile instance. When running on Java 9 and later, the JarFile will be multi-release JAR aware.
      Parameters:
        `f` - The JAR file to open
      Returns:
        A JarFile instance based on the provided file
      Throws:
        `java.io.IOException` - If an I/O error occurs creating the JarFile instance

    - #### jarFileIsMultiRelease

          public boolean jarFileIsMultiRelease​(java.util.jar.JarFile jarFile)

      Is this JarFile a multi-release JAR file.
      Parameters:
        `jarFile` - The JarFile to test
      Returns:
        `true` If it is a multi-release JAR file and is configured to behave as such.

    - #### jarFileRuntimeMajorVersion

          public int jarFileRuntimeMajorVersion()

    - #### canAccess

          public boolean canAccess​(java.lang.Object base,
                                   java.lang.reflect.AccessibleObject accessibleObject)

      Is the accessibleObject accessible (as a result of appropriate module exports) on the provided instance?
      Parameters:
        `base` - The specific instance to be tested.
        `accessibleObject` - The method/field/constructor to be tested.
      Returns:
        {code true} if the AccessibleObject can be accessed otherwise {code false}

    - #### isExported

          public boolean isExported​(java.lang.Class<?> type)

      Is the given class in an exported package?
      Parameters:
        `type` - The class to test
      Returns:
        Always `true` for Java 8. `true` if the enclosing package is exported for Java 9+

    - #### getModuleName

          public java.lang.String getModuleName​(java.lang.Class<?> type)

      What is the module of the given class?
      Parameters:
        `type` - The class to test
      Returns:
        Always `true` for Java 8. `true` if the enclosing package is exported for Java 9+

    - #### getExecutor

          public java.lang.Object getExecutor​(java.lang.Thread thread)
                                       throws java.lang.NoSuchFieldException,
                                              java.lang.SecurityException,
                                              java.lang.IllegalArgumentException,
                                              java.lang.IllegalAccessException

      Obtains the executor, if any, used to create the provided thread.
      Parameters:
        `thread` - The thread to examine
      Returns:
        The executor, if any, that created the provided thread
      Throws:
        `java.lang.NoSuchFieldException` - If a field used via reflection to obtain the executor cannot be found
        `java.lang.SecurityException` - If a security exception occurs while trying to identify the executor
        `java.lang.IllegalArgumentException` - If the instance object does not match the class of the field when obtaining a field value via reflection
        `java.lang.IllegalAccessException` - If a field is not accessible due to access restrictions

    - #### createVirtualThreadBuilder

          public java.lang.Object createVirtualThreadBuilder​(java.lang.String name)

      Create a thread builder for virtual threads using the given name to name the threads.
      Parameters:
        `name` - The base name for the threads
      Returns:
        The thread buidler for virtual threads

    - #### threadBuilderStart

          public void threadBuilderStart​(java.lang.Object threadBuilder,
                                         java.lang.Runnable command)

      Create a thread with the given thread builder and use it to execute the given runnable.
      Parameters:
        `threadBuilder` - The thread builder to use to create a thread
        `command` - The command to run