This code snippet gets the default keystore used by the Java keytool and displays the list of aliases along with the key type (certificate or private key). import java.io.File; import java.io.FileInputSt... The default keystore used by the above code is: $HOME/.keystore .

You can define environment variables in the Tomcat context.xml file like this: <?xml version="1.0" encoding="UTF-8"?> <Context... which is equivalent to the following in web.xml : <env-entry> <env-entry-name>varName</env-entr... In Java code, the variable can be looked up like this: // import javax.naming.Context; // import javax...

This is an example to replace a Java string with case insensitive match. Code: public class ReplaceTest { public static vo... Output: Done TEST tEst tESt Test Test TEST tEst tESt Te...

Some methods to search for a substring within a string: To know that a substring indeed exists within a string: boolean found = wholeString.contains(substring); To find where the substring is contained: int index = wholeString.indexOf(substring); If the substring is regex: boolean match = wholeString.matches(".*" + substri... Case insensitive match: convert both whole string and substring to lowercase, then compare. Or, use case insensitive flag for regex. Test code: import java.util.regex.*; public class Stri...

This is how to split a string using java.util.StringTokenizer : StringTokenizer tok = new StringTokenizer("this \... But don't do it ! According to JavaDoc : StringTokenizer is a legacy class that is retained for compatibility reasons although its use is discouraged in new code. It is recommended that anyone seeking this functionality use the split method of String or the java.util.regex package instead. Using String.split , the equivalent code is: String[] tokens = "this \tis\n a\t test".split("\... Also note that the following yield different results: String[] tokens1 = "this \tis\n a\t test".split("...

Sample code: import java.util.*; public class TestArrayL... If you use iterators, the for loop is equivalent to: for (Iterator<String> i = l.iterator(); i.hasNext(... The simplified for loop (or, for-each loop) can be used for arrays or objects that implement java.lang.Iterable . Note that by using generics, there's not need to down cast. But new for loop syntax doesn't down cast either. If List<String> is changed tp List<Object> , the code doesn't compile.

The goal is to read a file like this: for (String line: textFileReader) { // do s... This is the code: import java.io.*; import java.util.Iterator; ...

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...

Parsing a CVS file seemed to be a sore spot for software development. It's not simple enough that you can roll your own code in a couple of hours, and yet not deemed big enough for a full-fledged project. As a result, there are multiple libraries, each one with its own quirks. This is a summary of some simple tests I've done with five CSV parsers. Apache commons CSV parser : Does not escape backslash. The backslash is treated as literal if not proceeding a double quote, but then there's no way to have a backslash as the last character before the ending quote (even though it's a rare scenario). IOException thrown for unmatched quotes SuperCSV parser Can't handle escapes inside quotes Throws Exception for...

Demo code for CSV parsing with OpenCSV . Java code: import java.io.*; import au.com.bytecode.opencs... Test with a simple CSV file: psmith01,CLASS2B,Peter Smith 1,YEAR2,1,N,ADVANCED,... The parser worked correctly: Line 1 has 11 values: |psmith01| |CLASS2B|... Test with a more complicated CSV file: "psmith01 abc", "CLASS2B " , " Peter... Result: Line 1 has 4 values: |psmith01 abc| |CLASS... The parser: Escaped quote and backslash correctly Ignored spaces before the quotation mark - sometimes (see below) Counted spaces after the right quotation mark till the comma as content, including the right quotation mark (bug). Ignored improperly quoted item - silently (third line) Indeed, the OpenCSV parser has a problem with spaces: Input: "Smith, Jack", "210-345-8888" "Smith, J... Result: Line 1 has 2 values: | Smith, Jack| |210-3......