Update examples

Author: tmoskovitch

examples/src/main/java/com/twitter/clientlib/auth/OAuth20AppOnlyGetAccessToken.java

@@ -48,19 +48,17 @@
 public class OAuth20AppOnlyGetAccessToken {
 
   public static void main(String[] args) {
-    OAuth20AppOnlyGetAccessToken example = new OAuth20AppOnlyGetAccessToken();
-
-    OAuth2AccessToken accessToken = example.getAccessToken();
+    OAuth2AccessToken accessToken = getAccessToken();
     if (accessToken == null) {
       return;
     }
 
     // Setting the bearer token into TwitterCredentials
     TwitterCredentialsBearer credentials = new TwitterCredentialsBearer(accessToken.getAccessToken());
-    example.callApi(credentials);
+    callApi(credentials);
   }
 
-  public OAuth2AccessToken getAccessToken() {
+  public static OAuth2AccessToken getAccessToken() {
     TwitterOAuth20AppOnlyService service = new TwitterOAuth20AppOnlyService(
         System.getenv("TWITTER_CONSUMER_KEY"),
         System.getenv("TWITTER_CONSUMER_SECRET"));
@@ -78,7 +76,7 @@ public OAuth2AccessToken getAccessToken() {
     return accessToken;
   }
 
-  public void callApi(TwitterCredentialsBearer credentials) {
+  public static void callApi(TwitterCredentialsBearer credentials) {
     TwitterApi apiInstance = new TwitterApi(credentials);
 
     Set<String> tweetFields = new HashSet<>();

examples/src/main/java/com/twitter/clientlib/auth/OAuth20GetAccessToken.java

@@ -51,24 +51,23 @@
 public class OAuth20GetAccessToken {
 
   public static void main(String[] args) {
-    OAuth20GetAccessToken example = new OAuth20GetAccessToken();
     TwitterCredentialsOAuth2 credentials = new TwitterCredentialsOAuth2(System.getenv("TWITTER_OAUTH2_CLIENT_ID"),
         System.getenv("TWITTER_OAUTH2_CLIENT_SECRET"),
         System.getenv("TWITTER_OAUTH2_ACCESS_TOKEN"),
         System.getenv("TWITTER_OAUTH2_REFRESH_TOKEN"));
 
-    OAuth2AccessToken accessToken = example.getAccessToken(credentials);
+    OAuth2AccessToken accessToken = getAccessToken(credentials);
     if (accessToken == null) {
       return;
     }
 
     // Setting the access & refresh tokens into TwitterCredentialsOAuth2
     credentials.setTwitterOauth2AccessToken(accessToken.getAccessToken());
     credentials.setTwitterOauth2RefreshToken(accessToken.getRefreshToken());
-    example.callApi(credentials);
+    callApi(credentials);
   }
 
-  public OAuth2AccessToken getAccessToken(TwitterCredentialsOAuth2 credentials) {
+  public static OAuth2AccessToken getAccessToken(TwitterCredentialsOAuth2 credentials) {
     TwitterOAuth20Service service = new TwitterOAuth20Service(
         credentials.getTwitterOauth2ClientId(),
         credentials.getTwitterOAuth2ClientSecret(),
@@ -102,7 +101,7 @@ public OAuth2AccessToken getAccessToken(TwitterCredentialsOAuth2 credentials) {
     return accessToken;
   }
 
-  public void callApi(TwitterCredentialsOAuth2 credentials) {
+  public static void callApi(TwitterCredentialsOAuth2 credentials) {
     TwitterApi apiInstance = new TwitterApi(credentials);
 
     Set<String> tweetFields = new HashSet<>();

examples/src/main/java/com/twitter/clientlib/auth/OAuth20RefreshToken.java

@@ -48,8 +48,6 @@
 public class OAuth20RefreshToken {
 
   public static void main(String[] args) {
-    OAuth20RefreshToken example = new OAuth20RefreshToken();
-
     TwitterApi apiInstance = new TwitterApi(new TwitterCredentialsOAuth2(System.getenv("TWITTER_OAUTH2_CLIENT_ID"),
         System.getenv("TWITTER_OAUTH2_CLIENT_SECRET"),
         System.getenv("TWITTER_OAUTH2_ACCESS_TOKEN"),
@@ -63,10 +61,10 @@ public static void main(String[] args) {
       e.printStackTrace();
       return;
     }
-    example.callApi(apiInstance);
+    callApi(apiInstance);
   }
 
-  public void callApi(TwitterApi apiInstance) {
+  public static void callApi(TwitterApi apiInstance) {
     Set<String> tweetFields = new HashSet<>();
     tweetFields.add("author_id");
     tweetFields.add("id");

examples/src/main/java/com/twitter/clientlib/auth/OAuth20RevokeToken.java

@@ -47,7 +47,6 @@
 public class OAuth20RevokeToken {
 
   public static void main(String[] args) {
-    OAuth20RevokeToken example = new OAuth20RevokeToken();
     TwitterCredentialsOAuth2 credentials = new TwitterCredentialsOAuth2(System.getenv("TWITTER_OAUTH2_CLIENT_ID"),
         System.getenv("TWITTER_OAUTH2_CLIENT_SECRET"),
         System.getenv("TWITTER_OAUTH2_ACCESS_TOKEN"),
@@ -61,7 +60,7 @@ public static void main(String[] args) {
         "offline.access tweet.read users.read like.write space.read list.read tweet.write like.read");
 
     // Assuming that the access token is valid this call should be successful
-    example.callApi(apiInstance);
+    callApi(apiInstance);
     // Revoke the token
     try {
       service.revokeToken(credentials.getTwitterOauth2AccessToken(), TokenTypeHint.ACCESS_TOKEN);
@@ -71,10 +70,10 @@ public static void main(String[] args) {
       return;
     }
     // This call should fail
-    example.callApi(apiInstance);
+    callApi(apiInstance);
   }
 
-  public void callApi(TwitterApi apiInstance) {
+  public static void callApi(TwitterApi apiInstance) {
     Set<String> tweetFields = new HashSet<>();
     tweetFields.add("author_id");
     tweetFields.add("id");