Rename console/log getters

OutputStream -> Output, in an attempt to be less confusing, since the
functions return an InputStream.

While I'm here, improve the null context error message.

Bug: 243512115
Test: atest MicrodroidTests
Change-Id: Icce8d7b6da47719ca9d6ecdf85dd7e336630e02a
diff --git a/demo/java/com/android/microdroid/demo/MainActivity.java b/demo/java/com/android/microdroid/demo/MainActivity.java
index df6f44e..b5ae3d5 100644
--- a/demo/java/com/android/microdroid/demo/MainActivity.java
+++ b/demo/java/com/android/microdroid/demo/MainActivity.java
@@ -278,8 +278,8 @@
                 mVirtualMachine.setCallback(Executors.newSingleThreadExecutor(), callback);
                 mStatus.postValue(mVirtualMachine.getStatus());
 
-                InputStream console = mVirtualMachine.getConsoleOutputStream();
-                InputStream log = mVirtualMachine.getLogOutputStream();
+                InputStream console = mVirtualMachine.getConsoleOutput();
+                InputStream log = mVirtualMachine.getLogOutput();
                 mExecutorService.execute(new Reader("console", mConsoleOutput, console));
                 mExecutorService.execute(new Reader("log", mLogOutput, log));
             } catch (VirtualMachineException e) {
diff --git a/javalib/src/android/system/virtualmachine/VirtualMachine.java b/javalib/src/android/system/virtualmachine/VirtualMachine.java
index e750ae9..f9c81f4 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachine.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachine.java
@@ -729,7 +729,7 @@
      * @hide
      */
     @NonNull
-    public InputStream getConsoleOutputStream() throws VirtualMachineException {
+    public InputStream getConsoleOutput() throws VirtualMachineException {
         synchronized (mLock) {
             createVmPipes();
             return new FileInputStream(mConsoleReader.getFileDescriptor());
@@ -743,7 +743,7 @@
      * @hide
      */
     @NonNull
-    public InputStream getLogOutputStream() throws VirtualMachineException {
+    public InputStream getLogOutput() throws VirtualMachineException {
         synchronized (mLock) {
             createVmPipes();
             return new FileInputStream(mLogReader.getFileDescriptor());
diff --git a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
index 90b09c8..b814367 100644
--- a/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
+++ b/javalib/src/android/system/virtualmachine/VirtualMachineConfig.java
@@ -381,7 +381,7 @@
          * @hide
          */
         public Builder(@NonNull Context context) {
-            mContext = requireNonNull(context);
+            mContext = requireNonNull(context, "context must not be null");
             mDebugLevel = DEBUG_LEVEL_NONE;
             mNumCpus = 1;
         }
diff --git a/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java b/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java
index ede838b..9fb7d91 100644
--- a/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java
+++ b/tests/helper/src/java/com/android/microdroid/test/device/MicrodroidDeviceTestBase.java
@@ -202,8 +202,8 @@
                 throws VirtualMachineException, InterruptedException {
             vm.setCallback(mExecutorService, this);
             vm.run();
-            logVmOutputAndMonitorBootEvents(logTag, vm.getConsoleOutputStream(), "Console");
-            logVmOutput(logTag, vm.getLogOutputStream(), "Log");
+            logVmOutputAndMonitorBootEvents(logTag, vm.getConsoleOutput(), "Console");
+            logVmOutput(logTag, vm.getLogOutput(), "Log");
             mExecutorService.awaitTermination(300, TimeUnit.SECONDS);
         }