deps: switch from Jackson to GSON (#368)

* switch from Jackson to GSON

* format

Author: elharo

java-core/google-cloud-core/pom.xml

@@ -65,7 +65,7 @@
     </dependency>
     <dependency>
       <groupId>com.google.http-client</groupId>
-      <artifactId>google-http-client-jackson2</artifactId>
+      <artifactId>google-http-client-gson</artifactId>
     </dependency>
     <dependency>
       <groupId>com.google.protobuf</groupId>

java-core/google-cloud-core/src/main/java/com/google/cloud/ServiceOptions.java

@@ -30,8 +30,7 @@
 import com.google.api.client.json.GenericJson;
 import com.google.api.client.json.JsonFactory;
 import com.google.api.client.json.JsonObjectParser;
-import com.google.api.client.json.jackson2.JacksonFactory;
-import com.google.api.client.util.Charsets;
+import com.google.api.client.json.gson.GsonFactory;
 import com.google.api.core.ApiClock;
 import com.google.api.core.BetaApi;
 import com.google.api.core.CurrentMillisClock;
@@ -61,6 +60,7 @@
 import java.io.ObjectInputStream;
 import java.io.Serializable;
 import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.Locale;
 import java.util.Map;
 import java.util.Objects;
@@ -516,19 +516,18 @@ protected static String getServiceAccountProjectId() {
 
   @InternalApi("Visible for testing")
   static String getValueFromCredentialsFile(String credentialsPath, String key) {
-    String value = null;
     if (credentialsPath != null) {
       try (InputStream credentialsStream = new FileInputStream(credentialsPath)) {
-        JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
+        JsonFactory jsonFactory = GsonFactory.getDefaultInstance();
         JsonObjectParser parser = new JsonObjectParser(jsonFactory);
         GenericJson fileContents =
-            parser.parseAndClose(credentialsStream, Charsets.UTF_8, GenericJson.class);
-        value = (String) fileContents.get(key);
-      } catch (IOException e) {
-        // ignore
+            parser.parseAndClose(credentialsStream, StandardCharsets.UTF_8, GenericJson.class);
+        return (String) fileContents.get(key);
+      } catch (IOException | IllegalArgumentException ex) {
+        return null;
       }
     }
-    return value;
+    return null;
   }
 
   /**

java-core/google-cloud-core/src/test/java/com/google/cloud/ServiceOptionsTest.java

@@ -45,6 +45,7 @@
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.Set;
 import java.util.regex.Pattern;
@@ -441,9 +442,11 @@ public void testGetServiceAccountProjectId() throws Exception {
   public void testGetServiceAccountProjectId_badJson() throws Exception {
     File credentialsFile = File.createTempFile("credentials", ".json");
     credentialsFile.deleteOnExit();
-    Files.write("asdfghj".getBytes(), credentialsFile);
+    Files.write("asdfghj".getBytes(StandardCharsets.UTF_8), credentialsFile);
 
-    assertNull(ServiceOptions.getValueFromCredentialsFile(credentialsFile.getPath(), "project_id"));
+    String valueFromCredentialsFile =
+        ServiceOptions.getValueFromCredentialsFile(credentialsFile.getPath(), "project_id");
+    assertNull(valueFromCredentialsFile);
   }
 
   @Test