Package org.springframework.boot.devtools.restart

Class Restarter

java.lang.Object
org.springframework.boot.devtools.restart.Restarter
public class Restarter extends Object
Allows a running application to be restarted with an updated classpath. The restarter works by creating a new application ClassLoader that is split into two parts. The top part contains static URLs that don't change (for example 3rd party libraries and Spring Boot itself) and the bottom part contains URLs where classes and resources might be updated.

The Restarter should be initialized early to ensure that classes are loaded multiple times. Mostly the RestartApplicationListener can be relied upon to perform initialization, however, you may need to call initialize(String[]) directly if your SpringApplication arguments are not identical to your main method arguments.

By default, applications running in an IDE (i.e. those not packaged as "fat jars") will automatically detect URLs that can change. It's also possible to manually configure URLs or class file updates for remote restart scenarios.

Since:
1.3.0
Author:
Phillip Webb, Andy Wilkinson
See Also:

  • Constructor Details

    • Restarter

      protected Restarter(Thread thread, String[] args, boolean forceReferenceCleanup, RestartInitializer initializer)
      Internal constructor to create a new Restarter instance.
      Parameters:
      thread - the source thread
      args - the application arguments
      forceReferenceCleanup - if soft/weak reference cleanup should be forced
      initializer - the restart initializer
      See Also:

  • Method Details

    • initialize

      protected void initialize(boolean restartOnInitialize)

    • addUrls

      public void addUrls(Collection<URL> urls)
      Add additional URLs to be includes in the next restart.
      Parameters:
      urls - the urls to add

    • addClassLoaderFiles

      public void addClassLoaderFiles(ClassLoaderFiles classLoaderFiles)
      Add additional ClassLoaderFiles to be included in the next restart.
      Parameters:
      classLoaderFiles - the files to add

    • getThreadFactory

      public ThreadFactory getThreadFactory()
      Return a ThreadFactory that can be used to create leak safe threads.
      Returns:
      a leak safe thread factory

    • restart

      public void restart()
      Restart the running application.

    • restart

      public void restart(FailureHandler failureHandler)
      Restart the running application.
      Parameters:
      failureHandler - a failure handler to deal with application that doesn't start

    • start

      protected void start(FailureHandler failureHandler) throws Exception
      Start the application.
      Parameters:
      failureHandler - a failure handler for application that won't start
      Throws:
      Exception - in case of errors

    • relaunch

      protected Throwable relaunch(ClassLoader classLoader) throws Exception
      Relaunch the application using the specified classloader.
      Parameters:
      classLoader - the classloader to use
      Returns:
      any exception that caused the launch to fail or null
      Throws:
      Exception - in case of errors

    • stop

      protected void stop() throws Exception
      Stop the application.
      Throws:
      Exception - in case of errors

    • getOrAddAttribute

      public Object getOrAddAttribute(String name, ObjectFactory<?> objectFactory)

    • removeAttribute

      public Object removeAttribute(String name)

    • getInitialUrls

      public URL[] getInitialUrls()
      Return the initial set of URLs as configured by the RestartInitializer.
      Returns:
      the initial URLs or null

    • disable

      public static void disable()
      Initialize and disable restart support.

    • initialize

      public static void initialize(String[] args)
      Initialize restart support. See initialize(String[], boolean, RestartInitializer) for details.
      Parameters:
      args - main application arguments
      See Also:

    • initialize

      public static void initialize(String[] args, RestartInitializer initializer)
      Initialize restart support. See initialize(String[], boolean, RestartInitializer) for details.
      Parameters:
      args - main application arguments
      initializer - the restart initializer
      See Also:

    • initialize

      public static void initialize(String[] args, boolean forceReferenceCleanup)
      Initialize restart support. See initialize(String[], boolean, RestartInitializer) for details.
      Parameters:
      args - main application arguments
      forceReferenceCleanup - if forcing of soft/weak reference should happen on
      See Also:

    • initialize

      public static void initialize(String[] args, boolean forceReferenceCleanup, RestartInitializer initializer)
      Initialize restart support. See initialize(String[], boolean, RestartInitializer, boolean) for details.
      Parameters:
      args - main application arguments
      forceReferenceCleanup - if forcing of soft/weak reference should happen on
      initializer - the restart initializer
      See Also:

    • initialize

      public static void initialize(String[] args, boolean forceReferenceCleanup, RestartInitializer initializer, boolean restartOnInitialize)
      Initialize restart support for the current application. Called automatically by RestartApplicationListener but can also be called directly if main application arguments are not the same as those passed to the SpringApplication.
      Parameters:
      args - main application arguments
      forceReferenceCleanup - if forcing of soft/weak reference should happen on each restart. This will slow down restarts and is intended primarily for testing
      initializer - the restart initializer
      restartOnInitialize - if the restarter should be restarted immediately when the RestartInitializer returns non null results

    • getInstance

      public static Restarter getInstance()
      Return the active Restarter instance. Cannot be called before initialization.
      Returns:
      the restarter

    • clearInstance

      public static void clearInstance()
      Clear the instance. Primarily provided for tests and not usually used in application code.