Doubt on an Jsp file
Padma priya Gururajan
Ranch Hand
Posts: 437
posted 9 years ago
Consider the following jsp code:
<html>
<body>
<% String a = "aaa"; %>
<%! String a = "AAA"; %>
<% String b = "bbb"; %>
<%! String b = "BBB"; %>
<% out.println(a+b); %>
</body>
</html>
What will be the output?
Can anybody tell me why the output is aaabbb rather than AAABBB?
Please explain?
With regards,
Padma priya N.G.
<html>
<body>
<% String a = "aaa"; %>
<%! String a = "AAA"; %>
<% String b = "bbb"; %>
<%! String b = "BBB"; %>
<% out.println(a+b); %>
</body>
</html>
What will be the output?
Can anybody tell me why the output is aaabbb rather than AAABBB?
Please explain?
With regards,
Padma priya N.G.
Padma priya N.G.
Be the change you want to be - Mahatma Gandhi
Padma priya Gururajan
Ranch Hand
Posts: 437
Amol Nayak
Ranch Hand
Posts: 218
Sahid Khan
Ranch Hand
Posts: 41
posted 9 years ago
yes output will be aaabbb.
To know why you need to understand the difference between <% %> and <%! %>
<% %> is scriplet which appears inside jspService method as it is. Whereas <%! %> is a declaration which acts like instance variable declaration. So here you hide the variable "a" and "b" locally.
In fact compiled java file will look like..
HTH,
To know why you need to understand the difference between <% %> and <%! %>
<% %> is scriplet which appears inside jspService method as it is. Whereas <%! %> is a declaration which acts like instance variable declaration. So here you hide the variable "a" and "b" locally.
In fact compiled java file will look like..
HTH,
Padma priya Gururajan
Ranch Hand
Posts: 437
Amol Nayak
Ranch Hand
Posts: 218
Padma priya Gururajan
Ranch Hand
Posts: 437
vidhya jayapalan
Greenhorn
Posts: 12
posted 9 years ago
Padma priya,
when the JSP file gets translated to servlet
the variables in declaration element <%! ... %> becomes instance variables to the class.
<%! String a = "AAA"; %>
<%! String b = "BBB"; %>
and
the variables in Scriptlet element <% ... %> becomes local variables to the in built service method.
<% String a = "aaa"; %>
<% String b = "bbb"; %>
and
the scriptlet element <% out.println(a+b); %> will be in service method.
Since the local and instance variable names are the same, the local variables overrides instance variables.
Hence, aaabbb is the output.
Thanks,
Vidhya
when the JSP file gets translated to servlet
the variables in declaration element <%! ... %> becomes instance variables to the class.
<%! String a = "AAA"; %>
<%! String b = "BBB"; %>
and
the variables in Scriptlet element <% ... %> becomes local variables to the in built service method.
<% String a = "aaa"; %>
<% String b = "bbb"; %>
and
the scriptlet element <% out.println(a+b); %> will be in service method.
Since the local and instance variable names are the same, the local variables overrides instance variables.
Hence, aaabbb is the output.
Thanks,
Vidhya
Padma priya Gururajan
Ranch Hand
Posts: 437
Sundar Ram
Ranch Hand
Posts: 102
posted 9 years ago
A correction, variables cannot be overridden, they can only be shadowed.
Originally posted by vidhya jayapalan:
Padma priya,
Since the local and instance variable names are the same, the local variables overrides instance variables.
A correction, variables cannot be overridden, they can only be shadowed.
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Padma priya Gururajan
Ranch Hand
Posts: 437
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