diff --git a/java/compiler/impl/src/com/intellij/openapi/compiler/generic/GenericCompiler.java b/java/compiler/impl/src/com/intellij/openapi/compiler/generic/GenericCompiler.java
index b09c8e599626..87136283737b 100644
--- a/java/compiler/impl/src/com/intellij/openapi/compiler/generic/GenericCompiler.java
+++ b/java/compiler/impl/src/com/intellij/openapi/compiler/generic/GenericCompiler.java
@@ -25,6 +25,10 @@ import org.jetbrains.annotations.NotNull;
 
 /**
  * @author nik
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public abstract class GenericCompiler<Key, SourceState, OutputState> implements Compiler {
   protected static final KeyDescriptor<String> STRING_KEY_DESCRIPTOR = new EnumeratorStringDescriptor();
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassInstrumentingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassInstrumentingCompiler.java
index cfcf3373fa3f..4e5143aee495 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassInstrumentingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassInstrumentingCompiler.java
@@ -21,6 +21,10 @@ package com.intellij.openapi.compiler;
  * This affects the order of compiler calls:
  * The sequence in which compilers are called:
  * SourceGeneratingCompiler -> SourceInstrumentingCompiler -> TranslatingCompiler ->  ClassInstrumentingCompiler -> ClassPostProcessingCompiler -> PackagingCompiler -> Validator
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface ClassInstrumentingCompiler extends FileProcessingCompiler {
 }
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassPostProcessingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassPostProcessingCompiler.java
index 203facd2b02d..c4c3e8b40cf1 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassPostProcessingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/ClassPostProcessingCompiler.java
@@ -21,6 +21,10 @@ package com.intellij.openapi.compiler;
  * This affects the order of compiler calls:
  * The sequence in which compilers are called:
  * SourceGeneratingCompiler -> SourceInstrumentingCompiler -> TranslatingCompiler ->  ClassInstrumentingCompiler -> ClassPostProcessingCompiler -> PackagingCompiler -> Validator
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface ClassPostProcessingCompiler extends FileProcessingCompiler {
 }
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/CompilerManager.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/CompilerManager.java
index 4456665ef4bd..03d9be241ffb 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/CompilerManager.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/CompilerManager.java
@@ -63,6 +63,10 @@ public abstract class CompilerManager {
    * @param compiler compiler implementation 
    * @param inputTypes a set of filetypes that compiler accepts as input
    * @param outputTypes a set of filetypes that compiler can generate
+   *
+   * @deprecated this method is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+   * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+   * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
    */
   public abstract void addTranslatingCompiler(@NotNull TranslatingCompiler compiler, Set<FileType> inputTypes, Set<FileType> outputTypes);
 
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/CopyingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/CopyingCompiler.java
index 7d80c21daedf..758524e92426 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/CopyingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/CopyingCompiler.java
@@ -32,6 +32,10 @@ import java.util.List;
 
 /**
  * Compiler which copies the compiled files to a different directory.
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public abstract class CopyingCompiler implements PackagingCompiler{
   public abstract VirtualFile[] getFilesToCopy(CompileContext context);
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/GeneratingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/GeneratingCompiler.java
index 962bcb218e5e..af1fb1eb8dd7 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/GeneratingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/GeneratingCompiler.java
@@ -21,6 +21,10 @@ import com.intellij.openapi.vfs.VirtualFile;
 /**
  * A base interface for all compilers that generate new files. The generated files may be processed by other compilers.
  * Actual implementation should implement one of its subinterfaces. Currently only {@link SourceGeneratingCompiler} is available.
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface GeneratingCompiler extends Compiler, ValidityStateFactory, IntermediateOutputCompiler {
   /**
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/JavaSourceTransformingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/JavaSourceTransformingCompiler.java
index 27a397569aad..1194efcccba3 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/JavaSourceTransformingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/JavaSourceTransformingCompiler.java
@@ -19,6 +19,10 @@ import com.intellij.openapi.vfs.VirtualFile;
 
 /**
  * This compiler is called right before the java sources compiler.
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface JavaSourceTransformingCompiler extends Compiler {
 
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/PackagingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/PackagingCompiler.java
index e7e1350b41b9..3055e0ff654f 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/PackagingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/PackagingCompiler.java
@@ -23,6 +23,10 @@ import org.jetbrains.annotations.Nullable;
  * This affects the order of compiler calls.
  * The sequence in which compilers are called:
  * SourceGeneratingCompiler -> SourceInstrumentingCompiler -> TranslatingCompiler ->  ClassInstrumentingCompiler -> ClassPostProcessingCompiler -> PackagingCompiler -> Validator
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface PackagingCompiler extends FileProcessingCompiler{
   /**
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/SourceGeneratingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/SourceGeneratingCompiler.java
index 4c0b646658f6..2fe36ba202ba 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/SourceGeneratingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/SourceGeneratingCompiler.java
@@ -23,6 +23,10 @@ import com.intellij.openapi.vfs.VirtualFile;
  * This affects the order of compiler calls.
  * The sequence in which compilers are called:
  * SourceGeneratingCompiler -> SourceInstrumentingCompiler -> TranslatingCompiler ->  ClassInstrumentingCompiler -> ClassPostProcessingCompiler -> PackagingCompiler -> Validator
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface SourceGeneratingCompiler extends GeneratingCompiler {
   
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/TranslatingCompiler.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/TranslatingCompiler.java
index 3c56f8d9f67d..c5ce012c9ce6 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/TranslatingCompiler.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/TranslatingCompiler.java
@@ -26,6 +26,10 @@ import java.util.Collection;
  * This affects the order of compiler calls.
  * The sequence in which compilers are called:
  * SourceGeneratingCompiler -> SourceInstrumentingCompiler -> TranslatingCompiler ->  ClassInstrumentingCompiler -> ClassPostProcessingCompiler -> PackagingCompiler -> Validator
+ *
+ * @deprecated this interface is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public interface TranslatingCompiler extends Compiler {
 
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstruction.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstruction.java
index 148e1524e4a2..eed2e77c8030 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstruction.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstruction.java
@@ -15,6 +15,11 @@
  */
 package com.intellij.openapi.compiler.make;
 
+/**
+ * @deprecated this class is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
+ */
 public interface BuildInstruction {
   String getOutputRelativePath();
 
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstructionVisitor.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstructionVisitor.java
index 6ae9b33e062b..0bd62be958f7 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstructionVisitor.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildInstructionVisitor.java
@@ -15,7 +15,11 @@
  */
 package com.intellij.openapi.compiler.make;
 
-
+/**
+ * @deprecated this class is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
+ */
 public abstract class BuildInstructionVisitor {
   public boolean visitInstruction(BuildInstruction instruction) throws Exception {
     return true;
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipant.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipant.java
index 48022b6bf272..977772418589 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipant.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipant.java
@@ -20,7 +20,9 @@ import com.intellij.packaging.artifacts.Artifact;
 import org.jetbrains.annotations.Nullable;
 
 /**
- * @deprecated use interfaces from {@link com.intellij.openapi.compiler.Compiler}'s hierarchy instead
+ * @deprecated this class is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public abstract class BuildParticipant {
   public static final BuildParticipant[] EMPTY_ARRAY = new BuildParticipant[0];
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipantProvider.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipantProvider.java
index a0f46da79290..374e161549ad 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipantProvider.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/BuildParticipantProvider.java
@@ -24,7 +24,9 @@ import java.util.Collection;
 /**
  * @author nik
  *
- * @deprecated use interfaces from {@link com.intellij.openapi.compiler.Compiler}'s hierarchy instead
+ * @deprecated this class is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
  */
 public abstract class BuildParticipantProvider {
   public static final ExtensionPointName<BuildParticipantProvider> EXTENSION_POINT_NAME = ExtensionPointName.create("com.intellij.compiler.buildParticipantProvider");
diff --git a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/FileCopyInstruction.java b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/FileCopyInstruction.java
index 4109410aec00..c5636394cfe0 100644
--- a/java/compiler/openapi/src/com/intellij/openapi/compiler/make/FileCopyInstruction.java
+++ b/java/compiler/openapi/src/com/intellij/openapi/compiler/make/FileCopyInstruction.java
@@ -15,10 +15,13 @@
  */
 package com.intellij.openapi.compiler.make;
 
-import org.jetbrains.annotations.Nullable;
-
 import java.io.File;
 
+/**
+ * @deprecated this class is part of the obsolete build system which runs as part of the IDE process. Since IDEA 12 plugins need to
+ * integrate into 'external build system' instead (http://confluence.jetbrains.com/display/IDEADEV/External+Builder+API+and+Plugins).
+ * Since IDEA 13 users cannot switch to the old build system via UI and it will be completely removed in IDEA 14.
+ */
 public interface FileCopyInstruction extends BuildInstruction {
   File getFile();