review

Author: pvillard31

src/main/java/org/kohsuke/github/GitHubBuilder.java

@@ -161,7 +161,7 @@ static GitHubBuilder fromCredentials() throws IOException {
 
     private GitHubConnector connector;
 
-    private GitHubJackson jackson;
+    private GitHubJackson jackson = DefaultGitHubJackson.createDefault();
 
     private GitHubRateLimitChecker rateLimitChecker = new GitHubRateLimitChecker();
 
@@ -194,7 +194,7 @@ public GitHub build() throws IOException {
                 abuseLimitHandler,
                 rateLimitChecker,
                 authorizationProvider,
-                jackson != null ? jackson : DefaultGitHubJackson.createDefault());
+                jackson);
     }
 
     /**
@@ -212,29 +212,23 @@ public GitHubBuilder clone() {
     }
 
     /**
-     * Configures the client to use Jackson 3.x for JSON serialization/deserialization.
+     * Configures the client to use Jackson 2.x for JSON serialization/deserialization.
      *
      * <p>
-     * By default, Jackson 2.x is used. Call this method to use Jackson 3.x instead.
+     * By default, Jackson 3.x is used if available on the classpath, otherwise Jackson 2.x is used. Call this method to
+     * explicitly use Jackson 2.x.
      * </p>
      *
      * <h3>Example</h3>
      *
      * <pre>
-     * GitHub github = new GitHubBuilder().withOAuthToken("token").useJackson3().build();
+     * GitHub github = new GitHubBuilder().withOAuthToken("token").useJackson2().build();
      * </pre>
      *
-     * <p>
-     * <strong>Note:</strong> To use Jackson 3.x, you must add the Jackson 3 {@code tools.jackson.core:jackson-databind}
-     * dependency to your project.
-     * </p>
-     *
      * @return the GitHubBuilder
-     * @throws IllegalStateException
-     *             if Jackson 3.x is not available on the classpath
      */
-    public GitHubBuilder useJackson3() {
-        this.jackson = DefaultGitHubJackson.createJackson3();
+    public GitHubBuilder useJackson2() {
+        this.jackson = DefaultGitHubJackson.createJackson2();
         return this;
     }
 

src/main/java/org/kohsuke/github/internal/DefaultGitHubJackson.java

@@ -11,15 +11,16 @@
  * <h2>Usage</h2>
  *
  * <p>
- * By default, Jackson 2.x is used. To use Jackson 3.x, configure the {@link org.kohsuke.github.GitHubBuilder}:
+ * By default, Jackson 3.x is used if available on the classpath, otherwise Jackson 2.x is used. To explicitly use
+ * Jackson 2.x, configure the {@link org.kohsuke.github.GitHubBuilder}:
  * </p>
  *
  * <pre>
- * // Using Jackson 2.x (default)
+ * // Using default (Jackson 3.x if available, otherwise Jackson 2.x)
  * GitHub github = new GitHubBuilder().withOAuthToken("token").build();
  *
- * // Using Jackson 3.x
- * GitHub github = new GitHubBuilder().withOAuthToken("token").useJackson3().build();
+ * // Explicitly using Jackson 2.x
+ * GitHub github = new GitHubBuilder().withOAuthToken("token").useJackson2().build();
  * </pre>
  *
  * <h2>Jackson 3.x Dependencies</h2>
@@ -39,13 +40,18 @@ public final class DefaultGitHubJackson {
      * Creates the default {@link GitHubJackson} instance.
      *
      * <p>
-     * This method returns a Jackson 2.x implementation, which is the default and most stable option.
+     * This method returns a Jackson 3.x implementation if available on the classpath, otherwise it returns a Jackson
+     * 2.x implementation.
      * </p>
      *
-     * @return a GitHubJackson2 instance
+     * @return a GitHubJackson3 instance if Jackson 3.x is available, otherwise a GitHubJackson2 instance
      */
     public static GitHubJackson createDefault() {
-        return new GitHubJackson2();
+        if (isJackson3Available()) {
+            return new GitHubJackson3();
+        } else {
+            return new GitHubJackson2();
+        }
     }
 
     /**

src/main/java/org/kohsuke/github/internal/GitHubJackson.java

@@ -18,18 +18,19 @@
  *
  * <h2>Available Implementations</h2>
  * <ul>
- * <li>{@link GitHubJackson2} - Jackson 2.x implementation (default)</li>
- * <li>{@link GitHubJackson3} - Jackson 3.x implementation (requires additional dependencies)</li>
+ * <li>{@link GitHubJackson2} - Jackson 2.x implementation</li>
+ * <li>{@link GitHubJackson3} - Jackson 3.x implementation (default when available)</li>
  * </ul>
  *
  * <h2>Configuration</h2>
  * <p>
- * Use {@link org.kohsuke.github.GitHubBuilder#useJackson3()} to configure the client to use Jackson 3.x:
+ * By default, Jackson 3.x is used if available on the classpath, otherwise Jackson 2.x is used. Use
+ * {@link org.kohsuke.github.GitHubBuilder#useJackson2()} to explicitly use Jackson 2.x:
  * </p>
  *
  * <pre>
- * // Use Jackson 3.x
- * GitHub github = new GitHubBuilder().useJackson3().build();
+ * // Explicitly use Jackson 2.x
+ * GitHub github = new GitHubBuilder().useJackson2().build();
  * </pre>
  *
  * @author Pierre Villard

src/main/java/org/kohsuke/github/internal/GitHubJackson3.java

@@ -31,17 +31,10 @@
  * </p>
  *
  * <p>
- * To use Jackson 3.x, add the {@code tools.jackson.core:jackson-databind} dependency to your project.
+ * To use Jackson 3.x, add the {@code tools.jackson.core:jackson-databind} dependency to your project. When Jackson 3.x
+ * is available on the classpath, it is used by default.
  * </p>
  *
- * <p>
- * Then configure the GitHub client to use Jackson 3:
- * </p>
- *
- * <pre>
- * GitHub github = new GitHubBuilder().useJackson3().build();
- * </pre>
- *
  * @author Pierre Villard
  */
 public class GitHubJackson3 implements GitHubJackson {

src/test/java/org/kohsuke/github/GitHubJacksonTest.java

@@ -8,7 +8,7 @@
 import static org.hamcrest.CoreMatchers.*;
 
 /**
- * Tests for Jackson implementation selection via {@link GitHubBuilder#useJackson3()}.
+ * Tests for Jackson implementation selection via {@link GitHubBuilder#useJackson2()}.
  */
 public class GitHubJacksonTest extends AbstractGitHubWireMockTest {
 
@@ -20,30 +20,32 @@ public GitHubJacksonTest() {
     }
 
     /**
-     * Test that the default Jackson implementation is Jackson 2.
+     * Test that the default Jackson implementation is Jackson 3 when available.
      *
      * @throws IOException
      *             the io exception
      */
     @Test
-    public void testDefaultJacksonIsJackson2() throws IOException {
+    public void testDefaultJacksonIsJackson3WhenAvailable() throws IOException {
         gitHub = getGitHubBuilder().build();
         String implementationName = gitHub.getClient().getJacksonImplementationName();
-        assertThat(implementationName, startsWith("Jackson 2."));
+        if (DefaultGitHubJackson.isJackson3Available()) {
+            assertThat(implementationName, startsWith("Jackson 3."));
+        } else {
+            assertThat(implementationName, startsWith("Jackson 2."));
+        }
     }
 
     /**
-     * Test that Jackson 3 can be configured via builder when available.
+     * Test that Jackson 2 can be explicitly configured via builder.
      *
      * @throws IOException
      *             the io exception
      */
     @Test
-    public void testJackson3ViaBuilder() throws IOException {
-        if (DefaultGitHubJackson.isJackson3Available()) {
-            gitHub = getGitHubBuilder().useJackson3().build();
-            String implementationName = gitHub.getClient().getJacksonImplementationName();
-            assertThat(implementationName, startsWith("Jackson 3."));
-        }
+    public void testJackson2ViaBuilder() throws IOException {
+        gitHub = getGitHubBuilder().useJackson2().build();
+        String implementationName = gitHub.getClient().getJacksonImplementationName();
+        assertThat(implementationName, startsWith("Jackson 2."));
     }
 }

src/test/java/org/kohsuke/github/internal/DefaultGitHubJacksonTest.java

@@ -17,14 +17,19 @@ public DefaultGitHubJacksonTest() {
     }
 
     /**
-     * Test that createDefault returns Jackson 2 implementation.
+     * Test that createDefault returns Jackson 3 when available, otherwise Jackson 2.
      */
     @Test
     public void testCreateDefault() {
         GitHubJackson jackson = DefaultGitHubJackson.createDefault();
         assertThat(jackson, notNullValue());
-        assertThat(jackson, instanceOf(GitHubJackson2.class));
-        assertThat(jackson.getImplementationName(), startsWith("Jackson 2."));
+        if (DefaultGitHubJackson.isJackson3Available()) {
+            assertThat(jackson, instanceOf(GitHubJackson3.class));
+            assertThat(jackson.getImplementationName(), startsWith("Jackson 3."));
+        } else {
+            assertThat(jackson, instanceOf(GitHubJackson2.class));
+            assertThat(jackson.getImplementationName(), startsWith("Jackson 2."));
+        }
     }
 
     /**