If forgotPasswordForm.error is a String and not null, you cannot test the error condition with: <!-- This does not work! --> <c:if test="${forg... You have to use "not empty": <c:if test="${not empty forgotPasswordForm.error}"...

This is the error message: Error 6 initializing SQL*Plus SP2-0667: Message... It might be that the ORACLE_HOME environment variable is not properly set or a missing sp1<lang>.msb (for example sp1us.msb ) file. But for my Ubuntu system, there was no such thing as sp1<lang>.msb , and it wasn't caused by a missing ORACLE_HOME . The error was resolved after I restored the shared library file libsqlplusic.so .

It is well known that with the -D switch you can turn an ssh session into a socks proxy: ssh -D localhost:8080 remote_user@remote_host Now configure your browser to use " localhost:8080 " as a socks proxy and your web traffic is routed through remote_host via an ssh tunnel. But sometimes you encounter an error message like this: Disconnecting: Bad packet length - 1416586337 This is because sometimes, the ssh session outputs some "welcome" message into the tunnel, polluting the protocol stream between the client and the remote host. A safer way to establish an ssh socks proxy would be: ssh -N -D localhost:8080 remote_user@remote_host

String comparison operators: Operator Meaning -n str the length of str is nonzero. -z str the length of str is zero (0). str1 = str2 str1 and str2 are the same (note one equal sign, not two!). str1 != str2 str1 and str2 are not the same. str str is not a null string Examples: # empty string is not null if [ '' ]; then ... Numerical comparisons ( integer expressions only! ): Operator Meaning int1 -eq int2 int1 and int2 are numerically equal int1 -ne int2 int1 and int2 are numerically NOT equal int1 -gt int2 int1 is greater than int2 int1 -ge int2 int1 is greater than or equal to int2 int1 -lt int2 int1 is less than int2 int1 -le...

This code snippet import java.util.*; public class UncheckedCast ... fails with a compilation error and a warning: $ javac -Xlint:unchecked UncheckedCast.java Unc... Because List<String> is not a reifiable type, the Java Runtime does not have enough information to verify the type or do the type casting. This is fixed by changing List<String> to List<?> (or to the raw type List ): public static void main(String[] args) { Ob...

Parameterized types are considered different at compile time but not at runtime. This program fails compilation because List<Foo> is not the same as List<Bar> : import java.util.ArrayList; import java.util.Li... Error: $ javac SameErasure.java SameErasure.java:8: do... This also fails because List<Foo> and List<Bar> are considered the same: import java.util.ArrayList; import java.util.Li... Error: $ javac SameErasure.java SameErasure.java:11: n...

An XML schema is a definition of XML files, in XML. It plays the same role as old-time DTDs. Overall, an XML schema file looks like this: <schema attributeFormDefault = (qualified | u... The attribute meanings: targetNamespace : The name space targeted by the current schema definition. It can be any URI. id and version : For user convenience, the W3C spec defines no semantics for them. xml:lang : Natural language identifier defined by RFC 3306 . attributeFormDefault and elementFormDefault : Set default values for the form attribute for attribute and element declarations. blockDefault and finalDefault : Set default values for the block and final attributes for attribute and element declarations. The W3C defined some built-in datatypes . Examples of primitive datatypes are: string ,...

This is a sample struts-config.xml file for Struts 1.x . <?xml version="1.0" encoding="UTF-8"?> <!DO...

This utility class retrieves SSL certificates from the server and print them out to the stdout. The output can be saved to a file and imported to a Java keystore. This is useful in your test environment where the SSL certificate is self-signed. import java.io.InputStream; import java.io.Outp... Retrieve and import the a certificate: E:\test>java RetrieveSSLCert 192.168.69.144 8081 >...

grep is a versatile command with many variations (grep, egrep, fgrep, then various implementations). It uses a regula expression (regex) pattern to filter input. But then there are basic and extended flavors of regex - leading to even more confusion. And, beware that there are lots of bad examples of regex in the wild... There are two critical questions to ask when you use grep: which grep implementation are you using? what is the flavor of the regex? Here are some examples for gnu grep v2.7: # Find all numbers (no decimal point), basic regex... Use the -o flag to show only the matching part instead of the whole matching line: grep -o -E '\b[0-9]{2}\b' The good thing about the gnu grep is that it...