String in switch



My code looks like below:



<pre name="code" class="java">
 

 if (today.equals("monday")) {
 monday ();
 }
 else if (today.equals ("tuesday")) {
 tuesday();
 }
 else if (today.equals ("wednesday")) {
 wednesday();
 }
 else if (today.equals ("thursday")) {
 thrusday ();
 }
 else if (today.equals ("friday")) {
 friday ();
 }
 else if (today.equals ("saturday")) {
 saturday ();
 }
 else if (today.equals ("sunday")) {
 sunday ();
 }
 else {
 dayError ();
 }
 
 
</pre>



Now it looks like below



<pre name="code" class="java">
	 
 switch (today) {
 case "monday":
 monday ();
 break;
 case "tuesday":
 tuesday ();
 break;
 case "wednesday":
 wednesday ();
 break;
 case "thrusday":
 thrusday ();
 break;
 case "friday":
 friday ();
 break;
 case "saturday":
 saturday ();
 break;
 case "sunday":
 sunday ();
 break;
 default:
 dayError ();
 }
 
 
</pre>



Although I cannot tell if there is performance improvement, my code becomes cleaner saves some typing too. 



Try with resource



Java 7 has a new interface called AutoClosable. Every class that implements this interface can be used with try with 

resource mechanism. Here is my old code. Some lines removed for breviety.



<pre name="code" class="java">
	
 try {
 Statement statement=connection.createStatement ();
 try {
 Resultset resultset = 
 statement.executeQuery ("select * from table_a"); 

 // code here
 
 resultset.close ();
 }
 catch (SQLException e) {
 }

 statement.close (); 

 }
 catch (SQLException exception) {
 exception.getMessage ();
 }
 
 
</pre>



The new Java 7 equivalent code.



<pre name="code" class="java">
 
 try (Statement statement = connection.createStatement ()) {
 	try (Resultset resultset = 
 statement.executeQuery ("select * from table_a")) {

 // your code here

 }
 catch (SQLExceptione res_exception) {
 }
 }
 catch (SQLException exception) {
 }
 
 
</pre>



Note that we did not close statement and resultset. They are closed as they go out of scope. It is also legal to have several lines/resources in the new try statement. The following is a variant of the above code, may be to 

your liking if you don't like nested try-catch blocks.



<pre name="code" class="java">
 
 // Execution is left to right;

 try (Statement statement = connection.createStatement ();
 ResultSet resultset = 
 statement.executeQuery ("select * from table");

 // your code here

 }
 catch (SQLException exception) {
 }
 
 
</pre>




The obvious advantage is you need not worry about freeing resources. 



You can find the complete list of Java 7 classes 

that implements AutoClosable interface <a href="http://download.oracle.com/javase/7/docs/api/java/lang/AutoCloseable.html" 

target="_blank" class="news_link">in the AutoClosable JavaDoc</a>.




Multi catch



 Consider this old code, a catch block for each thrown exception.



<pre name="code" class="java">
	
 try {

 Class.forName("com.mysql.jdbc.Driver").newInstance();
 connection = DriverManager.getConnection(dburl); 

 } catch (SQLException e) {
 //
 }
 catch (ClassNotFoundException e) {
 }
 catch (InstantiationException e) {
 }
 catch (IllegalAccessException e) {
 //
 } finally {
 return connection;
 }
 
 
</pre>



Becomes the code below. All thrown exceptions caught in one catch block lumped together by the pipe operator.



<pre name="code" class="java">
 
	
 try {
 Class.forName("com.mysql.jdbc.Driver").newInstance();
 connection = DriverManager.getConnection(dburl); 

 } catch (SQLException | ClassNotFoundException |
 InstantiationException | IllegalAccessException e) {
 connection = null;
 } finally {
 return connection;
 }
 
 
</pre>



This is just my experience. There are more new constructs in Java 7. You may want to visit the <a 

href="http://download.oracle.com/javase/7/docs/api/overview-summary.html" target="_blank" class="news_link">Java 7 specifications 

site in this link. </a>



Good luck.

My experience with some of the new Java 7 features