### Question:
JSONBodyParametersApplier implements OAuthParametersApplier { public OAuthMessage applyOAuthParameters(OAuthMessage message, Map<String, Object> params) throws OAuthSystemException { String json = null; try { json = JSONUtils.buildJSON(params); message.setBody(json); return message; } catch (Throwable e) { throw new OAuthSystemException(e); } }  OAuthMessage applyOAuthParameters(OAuthMessage message, Map<String, Object> params);  }### Answer:
@Test public void testApplyOAuthParameters() throws Exception { OAuthParametersApplier app = new JSONBodyParametersApplier(); Map<String, Object> params = new HashMap<String, Object>(); params.put(OAuth.OAUTH_EXPIRES_IN, 3600l); params.put(OAuth.OAUTH_ACCESS_TOKEN, "token_authz"); params.put(OAuth.OAUTH_CODE, "code_"); params.put(OAuth.OAUTH_SCOPE, "read"); params.put(OAuth.OAUTH_STATE, "state"); params.put("empty_param", ""); params.put("null_param", null); params.put("", "some_value"); params.put(null, "some_value"); OAuthMessage message = new DummyOAuthMessage("http: app.applyOAuthParameters(message, params); String msgBody = message.getBody(); Map<String, Object> map = JSONUtils.parseJSON(msgBody); assertEquals(3600L, map.get(OAuth.OAUTH_EXPIRES_IN)); assertEquals("token_authz", map.get(OAuth.OAUTH_ACCESS_TOKEN)); assertEquals("code_", map.get(OAuth.OAUTH_CODE)); assertEquals("read", map.get(OAuth.OAUTH_SCOPE)); assertEquals("state", map.get(OAuth.OAUTH_STATE)); assertNull(map.get("empty_param")); assertNull(map.get("null_param")); assertNull(map.get("")); assertNull(map.get(null)); }