diff --git a/extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java b/extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java
index 15ffe5f141d..0190668a70a 100644
--- a/extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java
+++ b/extensions/cronet/src/main/java/com/google/android/exoplayer2/ext/cronet/CronetDataSource.java
@@ -416,8 +416,10 @@ private UrlRequest buildRequest(DataSpec dataSpec) throws OpenException {
         executor, cronetEngine);
     // Set the headers.
     synchronized (requestProperties) {
-      if (dataSpec.postBody != null && !requestProperties.containsKey(CONTENT_TYPE)) {
-        throw new OpenException("POST request must set Content-Type", dataSpec, Status.IDLE);
+      if (dataSpec.postBody != null && dataSpec.postBody.length != 0
+          && !requestProperties.containsKey(CONTENT_TYPE)) {
+        throw new OpenException("POST request with non-empty body must set Content-Type", dataSpec,
+            Status.IDLE);
       }
       for (Entry<String, String> headerEntry : requestProperties.entrySet()) {
         requestBuilder.addHeader(headerEntry.getKey(), headerEntry.getValue());
@@ -434,10 +436,13 @@ private UrlRequest buildRequest(DataSpec dataSpec) throws OpenException {
       }
       requestBuilder.addHeader("Range", rangeValue.toString());
     }
-    // Set the body.
+    // Set the method and (if non-empty) the body.
     if (dataSpec.postBody != null) {
-      requestBuilder.setUploadDataProvider(new ByteArrayUploadDataProvider(dataSpec.postBody),
-          executor);
+      requestBuilder.setHttpMethod("POST");
+      if (dataSpec.postBody.length != 0) {
+        requestBuilder.setUploadDataProvider(new ByteArrayUploadDataProvider(dataSpec.postBody),
+            executor);
+      }
     }
     return requestBuilder.build();
   }
diff --git a/library/src/main/java/com/google/android/exoplayer2/drm/HttpMediaDrmCallback.java b/library/src/main/java/com/google/android/exoplayer2/drm/HttpMediaDrmCallback.java
index 14329d47ee1..65e41dd91e0 100644
--- a/library/src/main/java/com/google/android/exoplayer2/drm/HttpMediaDrmCallback.java
+++ b/library/src/main/java/com/google/android/exoplayer2/drm/HttpMediaDrmCallback.java
@@ -71,7 +71,7 @@ public HttpMediaDrmCallback(String defaultUrl, HttpDataSource.Factory dataSource
   @Override
   public byte[] executeProvisionRequest(UUID uuid, ProvisionRequest request) throws IOException {
     String url = request.getDefaultUrl() + "&signedRequest=" + new String(request.getData());
-    return executePost(url, null, null);
+    return executePost(url, new byte[0], null);
   }
 
   @Override
@@ -81,6 +81,7 @@ public byte[] executeKeyRequest(UUID uuid, KeyRequest request) throws Exception
       url = defaultUrl;
     }
     Map<String, String> requestProperties = new HashMap<>();
+    requestProperties.put("Content-Type", "application/octet-stream");
     if (C.PLAYREADY_UUID.equals(uuid)) {
       requestProperties.putAll(PLAYREADY_KEY_REQUEST_PROPERTIES);
     }
@@ -93,8 +94,6 @@ public byte[] executeKeyRequest(UUID uuid, KeyRequest request) throws Exception
   private byte[] executePost(String url, byte[] data, Map<String, String> requestProperties)
       throws IOException {
     HttpDataSource dataSource = dataSourceFactory.createDataSource();
-    // Note: This will be overridden by a Content-Type in requestProperties, if one is set.
-    dataSource.setRequestProperty("Content-Type", "application/octet-stream");
     if (requestProperties != null) {
       for (Map.Entry<String, String> requestProperty : requestProperties.entrySet()) {
         dataSource.setRequestProperty(requestProperty.getKey(), requestProperty.getValue());
diff --git a/library/src/main/java/com/google/android/exoplayer2/upstream/DefaultHttpDataSource.java b/library/src/main/java/com/google/android/exoplayer2/upstream/DefaultHttpDataSource.java
index 34ec76b6739..b326c41b18e 100644
--- a/library/src/main/java/com/google/android/exoplayer2/upstream/DefaultHttpDataSource.java
+++ b/library/src/main/java/com/google/android/exoplayer2/upstream/DefaultHttpDataSource.java
@@ -413,11 +413,16 @@ private HttpURLConnection makeConnection(URL url, byte[] postBody, long position
     connection.setInstanceFollowRedirects(followRedirects);
     connection.setDoOutput(postBody != null);
     if (postBody != null) {
-      connection.setFixedLengthStreamingMode(postBody.length);
-      connection.connect();
-      OutputStream os = connection.getOutputStream();
-      os.write(postBody);
-      os.close();
+      connection.setRequestMethod("POST");
+      if (postBody.length == 0) {
+        connection.connect();
+      } else  {
+        connection.setFixedLengthStreamingMode(postBody.length);
+        connection.connect();
+        OutputStream os = connection.getOutputStream();
+        os.write(postBody);
+        os.close();
+      }
     } else {
       connection.connect();
     }