Java 8. Java 8. Does whatever Java 8 can.

Default methods, everywhere.
Arrow types, switch on strings.
Lambdas!
Here comes Java 8.

src/main/java/dan200/computercraft/api/lua/ILuaTask.java

@@ -16,6 +16,7 @@ import javax.annotation.Nullable;
  * @see ILuaContext#executeMainThreadTask(ILuaTask)
  * @see ILuaContext#issueMainThreadTask(ILuaTask)
  */
+@FunctionalInterface
 public interface ILuaTask
 {
     /**

src/main/java/dan200/computercraft/api/media/IMediaProvider.java

@@ -16,6 +16,7 @@ import javax.annotation.Nullable;
  *
  * @see dan200.computercraft.api.ComputerCraftAPI#registerMediaProvider(IMediaProvider)
  */
+@FunctionalInterface
 public interface IMediaProvider
 {
     /**

src/main/java/dan200/computercraft/api/peripheral/IPeripheral.java

@@ -91,7 +91,9 @@ public interface IPeripheral
      *                 computers can be attached to a peripheral at once.
      * @see #detach
      */
-    void attach( @Nonnull IComputerAccess computer );
+    default void attach( @Nonnull IComputerAccess computer )
+    {
+    }
 
     /**
      * Is called when a computer is detaching from the peripheral.
@@ -108,7 +110,9 @@ public interface IPeripheral
      *                 computers can be attached to a peripheral at once.
      * @see #detach
      */
-    void detach( @Nonnull IComputerAccess computer );
+    default void detach( @Nonnull IComputerAccess computer )
+    {
+    }
 
     /**
      * Determine whether this peripheral is equivalent to another one.

src/main/java/dan200/computercraft/api/peripheral/IPeripheralProvider.java

@@ -18,6 +18,7 @@ import javax.annotation.Nullable;
  *
  * @see dan200.computercraft.api.ComputerCraftAPI#registerPeripheralProvider(IPeripheralProvider)
  */
+@FunctionalInterface
 public interface IPeripheralProvider
 {
     /**

src/main/java/dan200/computercraft/api/pocket/IPocketUpgrade.java

@@ -74,7 +74,9 @@ public interface IPocketUpgrade
      * @param peripheral The peripheral for this upgrade.
      * @see #createPeripheral(IPocketAccess)
      */
-    void update( @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral );
+    default void update( @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral )
+    {
+    }
 
     /**
      * Called when the pocket computer is right clicked.
@@ -87,5 +89,8 @@ public interface IPocketUpgrade
      * access the GUI.
      * @see #createPeripheral(IPocketAccess)
      */
-    boolean onRightClick( @Nonnull World world, @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral );
+    default boolean onRightClick( @Nonnull World world, @Nonnull IPocketAccess access, @Nullable IPeripheral peripheral )
+    {
+        return false;
+    }
 }

src/main/java/dan200/computercraft/api/redstone/IBundledRedstoneProvider.java

@@ -17,6 +17,7 @@ import javax.annotation.Nonnull;
  *
  * @see dan200.computercraft.api.ComputerCraftAPI#registerBundledRedstoneProvider(IBundledRedstoneProvider)
  */
+@FunctionalInterface
 public interface IBundledRedstoneProvider
 {
     /**

src/main/java/dan200/computercraft/api/turtle/ITurtleCommand.java

@@ -15,6 +15,7 @@ import javax.annotation.Nonnull;
  *
  * @see ITurtleAccess#executeCommand(ILuaContext, ITurtleCommand)
  */
+@FunctionalInterface
 public interface ITurtleCommand
 {
     /**

src/main/java/dan200/computercraft/api/turtle/ITurtleUpgrade.java

@@ -136,5 +136,7 @@ public interface ITurtleUpgrade
      * @param turtle Access to the turtle that the upgrade resides on.
      * @param side   Which side of the turtle (left or right) the upgrade resides on.
      */
-    void update( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side );
+    default void update( @Nonnull ITurtleAccess turtle, @Nonnull TurtleSide side )
+    {
+    }
 }