some annotations added

platform/platform-api/src/com/intellij/execution/process/OSProcessHandler.java

@@ -100,7 +100,7 @@ public class OSProcessHandler extends BaseOSProcessHandler {
    * @param process Process
    * @return True if process tree has been successfully killed.
    */
-  protected boolean killProcessTree(final Process process) {
+  protected boolean killProcessTree(@NotNull Process process) {
     LOG.debug("killing process tree");
     final boolean destroyed = OSProcessManager.getInstance().killProcessTree(process);
     if (!destroyed) {

platform/platform-api/src/com/intellij/execution/process/ProcessOutput.java

@@ -18,6 +18,7 @@ package com.intellij.execution.process;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.util.text.StringUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.List;
 
@@ -39,30 +40,35 @@ public class ProcessOutput {
     myExitCode = exitCode;
   }
 
-  public void appendStdout(String text) {
+  public void appendStdout(@Nullable String text) {
     myStdoutBuilder.append(text);
   }
 
-  public void appendStderr(String text) {
+  public void appendStderr(@Nullable String text) {
     myStderrBuilder.append(text);
   }
 
+  @NotNull
   public String getStdout() {
     return myStdoutBuilder.toString();
   }
 
+  @NotNull
   public String getStderr() {
     return myStderrBuilder.toString();
   }
 
+  @NotNull
   public List<String> getStdoutLines() {
     return splitLines(getStdout());
   }
 
+  @NotNull
   public List<String> getStderrLines() {
     return splitLines(getStderr());
   }
 
+  @NotNull
   private static List<String> splitLines(String s) {
     String converted = StringUtil.convertLineSeparators(s);
     return StringUtil.split(converted, "\n");

python/src/com/jetbrains/python/sdk/PySdkUtil.java

@@ -139,6 +139,7 @@ public class PySdkUtil {
   private static ProcessOutput getOutputForException(final Exception e) {
     LOG.warn(e);
     return new ProcessOutput() {
+      @NotNull
       @Override
       public String getStderr() {
         String err = super.getStderr();