While trying to compile my java class files with the 1.6 java compiler, I came across an error message that read :
“no unique maximal instance exists for type variable U with upper bounds U”
The weird thing was that the file compiled just fine in eclipse!
On further probing I realized it’s a javac bug (check the bug here)
Here’s the workaround -
Bug Scenario :
public class SomeObject {
<U extends SomeObject> U foo1() throws Exception {
SomeObject obj = new SomeObject();
return obj.foo1();
}
}
Solve this way :
public class SomeObject {
<U extends SomeObject> U foo1() throws Exception {
SomeObject obj = new SomeObject();
return obj.<U>foo1();
}
}
Javascript has an inbuilt substring function which helps to extract parts of a string.
substring(start, stop) :
start (mandatory) - The starting index
stop (optional) - The index to stop extraction
Example: If you want to find the first 3 alphabets in the word INDIA, the code would be
var name = “INDIA”;
var firstThreeLetters = name.substring(0,3);
alert(firstThreeLetters);
The alert would display : IND
Note: Here start is 0 hence the extraction starts from the letter in the 0th position i.e. the first letter. The stop index is 3 which means extraction would stop at index 3 (the letter at index 3 will not be extracted)
Since stop is optional, if you only specify the start parameter, all the letters after the starting index (including the one at the start) would be extracted.
Example: Consider the same example as above, for the word INDIA if we were to give the start as 1
var name = “INDIA”;
var extractedLetters = name.substring(1);
alert(extractedLetters);
The alert would display NDIA as the output of the javascript substring method.
————————————————————————————
Indepth Analysis of Javascript substring
Let’s try and create our own Javascript substring function.
String.prototype.mySubstring = function(start,stop) {
var charArray = this.split(’);
var temp = “”;
for(var i=start;<stop;i++)
{
temp = temp + charArray[i];
}
return temp;
}
Now, you can use this function instead of the default substring function. Include the above code in any page and you can use mySubstring inside any javascript function.
Example:
var name = “INDIA”;
var extractedLetters = name.mySubstring(0,3);
alert(extractedLetters);
The alert would display IND thus emulating the real Javascript substring function!
Note: This method is just a food for thought. To help you understand how exactly such methods would be implemented. For all practical purposes use the default substring function of Javascript.
You can lock your windows desktop by clicking on “windows key + L“. There is another way to do this. By creating a shortcut.
Right Click on your desktop and select
New -> Shortcut.
A shortcut will be created and a dialog box would pop up.
Copy paste %windir%\system32\rundll32.exe user32.dll,LockWorkStation into the text box of the dialog.
Click Next. Type any name you like.
A desktop shortcut with the name that you gave would be created. Double click anytime to lock your computer.
