Address thread-safety concerns raised in #357 (#370)

* Address thread-safety concerns raised in #357

* Add missing property for merging of DefaultsConfigContext

Author: tjcelaya

java-manta-client-unshaded/src/main/java/com/joyent/manta/config/BaseChainedConfigContext.java

@@ -22,139 +22,139 @@ public abstract class BaseChainedConfigContext implements SettableConfigContext<
     /**
      * Manta service endpoint.
      */
-    private String mantaURL;
+    private volatile String mantaURL;
 
     /**
      * Account associated with the Manta service.
      */
-    private String account;
+    private volatile String account;
 
     /**
      * RSA key fingerprint of the private key used to access Manta.
      */
-    private String mantaKeyId;
+    private volatile String mantaKeyId;
 
     /**
      * Path on the filesystem to the private RSA key used to access Manta.
      */
-    private String mantaKeyPath;
+    private volatile String mantaKeyPath;
 
     /**
      * General connection timeout for the Manta service.
      */
-    private Integer timeout;
+    private volatile Integer timeout;
 
     /**
      * Number of times to retry failed requests.
      */
-    private Integer retries;
+    private volatile Integer retries;
 
     /**
      * The maximum number of open connections to the Manta API.
      */
-    private Integer maxConnections;
+    private volatile Integer maxConnections;
 
     /**
      * Private key content. This shouldn't be set if the MantaKeyPath is set.
      */
-    private String privateKeyContent;
+    private volatile String privateKeyContent;
 
     /**
      * Optional password for private key.
      */
-    private String password;
+    private volatile String password;
 
     /**
      * Size of buffer in bytes to use to buffer streams of HTTP data.
      */
-    private Integer httpBufferSize;
+    private volatile Integer httpBufferSize;
 
     /**
      * Comma delimited list of supported TLS protocols.
      */
-    private String httpsProtocols;
+    private volatile String httpsProtocols;
 
     /**
      * Comma delimited list of supported TLS ciphers.
      */
-    private String httpsCipherSuites;
+    private volatile String httpsCipherSuites;
 
     /**
      * Flag indicating if HTTP signatures are turned off.
      */
-    private Boolean noAuth;
+    private volatile Boolean noAuth;
 
     /**
      * Flag indicating if HTTP signature native code generation is turned off.
      */
-    private Boolean disableNativeSignatures;
+    private volatile Boolean disableNativeSignatures;
 
     /**
      * Time in milliseconds to cache HTTP signature headers.
      */
-    private Integer tcpSocketTimeout;
+    private volatile Integer tcpSocketTimeout;
 
     /**
      * Time in milliseconds to wait for a connection from the connection pool.
      */
-    private Integer connectionRequestTimeout;
+    private volatile Integer connectionRequestTimeout;
 
     /**
      * Flag indicating if we verify the uploaded file's checksum against the
      * server's checksum (MD5).
      */
-    private Boolean verifyUploads;
+    private volatile Boolean verifyUploads;
 
     /**
      * Number of bytes to read into memory for a streaming upload before
      * deciding if we want to load it in memory before send it.
      */
-    private Integer uploadBufferSize;
+    private volatile Integer uploadBufferSize;
 
     /**
      * Flag indicating when client-side encryption is enabled.
      */
-    private Boolean clientEncryptionEnabled;
+    private volatile Boolean clientEncryptionEnabled;
 
     /**
      * The unique identifier of the key used for encryption.
      */
-    private String encryptionKeyId;
+    private volatile String encryptionKeyId;
 
     /**
      * The client encryption algorithm name in the format of
      * <code>cipher/mode/padding state</code>.
      */
-    private String encryptionAlgorithm;
+    private volatile String encryptionAlgorithm;
 
     /**
      * Flag indicating when downloading unencrypted files is allowed in
      * encryption mode.
      */
-    private Boolean permitUnencryptedDownloads;
+    private volatile Boolean permitUnencryptedDownloads;
 
     /**
      * Enum specifying if we are in strict ciphertext authentication mode or not.
      */
-    private EncryptionAuthenticationMode encryptionAuthenticationMode;
+    private volatile EncryptionAuthenticationMode encryptionAuthenticationMode;
 
     /**
      * Path to the private encryption key on the filesystem (can't be used if
      * private key bytes is not null).
      */
-    private String encryptionPrivateKeyPath;
+    private volatile String encryptionPrivateKeyPath;
 
     /**
      * Private encryption key data (can't be used if private key path is not null).
      */
-    private byte[] encryptionPrivateKeyBytes;
+    private volatile byte[] encryptionPrivateKeyBytes;
 
     /**
      * Flag indicating the the mantaKeyPath has been set only by the defaults.
      * True = set by defaults.
      * False = overwritten by non-defaults.
      */
-    private boolean mantaKeyPathSetOnlyByDefaults = false;
+    private volatile boolean mantaKeyPathSetOnlyByDefaults = false;
 
     /** Singleton instance of default configuration for easy reference. */
     public static final ConfigContext DEFAULT_CONFIG =