Oracle sqlplus command line tools does not support command line editing out-of-the-box. But on Linux there's a handy utility that enables command line editing with any command line tool: rlwrap - readline wrapper. Install rlwrap: $ sudo apt-get install rlwrap Create a keywords file .sql.dict (optional, but convenient): false null true access add as asc begin by chec... It would be nice to add the tables names also. Create an alias for sqlplus (put it in .bashrc ): alias sqlplus='rlwrap -f $HOME/.sql.dict sqlplus'

The Android unit test framework is based on JUnit 3 , not JUnit 4. Test cases have to extend junit.framework.TestCase or a subclass (such as android.test.InstrumentationTestCase ). Tests are identified by public methods whose name starts with test , not methods annotated with @Test (as in JUnit 4). An Android test suite is packaged as an APK, just like the application being tested. To create a test package, first you need to identify the application package it is testing. Google suggests to put the test package source in a directory named tests/ alongside the src/ directory of the main application. At runtime, Android instrumentation loads both the test package and the application under test into the same process. Therefore, the tests can invoke methods on...

When you pass parameters from shell to Java, the list arguments may be messed up if there are spaces in the values. Start with a simple Java test class: public class EchoParams { public static voi... Tests: $ java EchoParams a b c Arg: a Arg: b Arg... Now wrap the command in a shell script ( echoparams.sh ): #!/bin/sh java EchoParams $* Tests: $ ./echoparams.sh a b c Arg: a Arg: b Arg... The quotes had no effect on the parameters list. Changing $* to $@ produces the same results. The correct way to quote the args list is: "$@" #!/bin/sh java EchoParams "$@" Test: $ ./echoparams.sh a b "c d" "1 2 3 4 5" Arg: a ...

Some javap usage examples. Start from HelloWorld.java : @Deprecated public class HelloWorld { pu... javap -c HelloWorld outputs: Compiled from "HelloWorld.java" public class He... javap -v HelloWorld outputs ( -v for verbose mode): Compiled from "HelloWorld.java" public class He... The output consists of: " Compiled from... " header Class attributes. For the HelloWorld example, there are two: SourceFile and Deprecated . Minor and major class file version Constant pool Disassembled code LineNumberTable for debugging purposes. javap by default only prints package/protected/public members. To display all members including private, use the -p switch. javap -v -p HelloWorld

This is an odd-ball content provider in that it doesn't provide database records, but provides a resource as a stream. It can be used to provide media files or XML resources. Start the project with: tools/android create project --package com.android... Create assets directory and add an XML file ( assets/demo.xml ): <? xml version="1.0" encoding="UTF-8"?> <people... Edit the layout ( res/layout/main.xml ): <?xml version="1.0" encoding="utf-8"?> <LinearL... Edit src/com/android/cptest/Dummy.java : package com.android.cptest; import java.io.... Add content provider ( src/com/android/cptest/XmlResource.java ): package com.android.cptest; import java.io.... Update AndroidManifest.xml : <?xml version="1.0" encoding="utf-8"?> <manifes... Add this section to the end of build.xml : <target name="-package-resources"> <ech... Build and install: ant install Screenshot: Remove the Dummy activity ( AndroidManifest.xml ): <?xml version="1.0" encoding="utf-8"?> <manifes... Create a new project for...

When you create a new key with Java keytool , it wraps the public key in a self signed certificate. You can generate a certificate signing request with the keytool -certreq command. After a certificate authority (CA) signs the certificate request, you can import the certificate received (a .crt file) back into the key store. Instead of using a CA, you can sign the certificate request with another key (with openssl, for example). If the certificate is not signed by a CA, you'll receive an error: $ keytool -import -alias android-root -file androi... To fix the problem, import the certificate of the signer: $ keytool -import -trustcacerts -file openssl.crt ... Import the certificate again (alias is the alias of the private key whose certificate was...

With StringBuffer/StringBuilder: public class ReverseString { private static... Without StringBuffer/StringBuilder: public class ReverseString { private static...

cURL is a command line tool for transferring files with URL syntax. The main purpose and use for cURL is to automate unattended file transfers or sequences of operations. It's really easy to see HTTP headers with curl: C:\>curl --head http://www.google.com HTTP/1.0 ... or, headers and page together (dump headers to stdout): $ curl --dump-header - http://www.google.com HTTP/... Download openssl from openssl.org: curl http://www.openssl.org/source/openssl-0.9.6m.... C:\>curl --help Usage: curl [options...] <url> ...

Use the \d command to show information about a table: postgres=# \d patchtype Table ...

Use the \d command to list tables, sequences, etc.: postgres=# \d List of relations ...

Code: package hello.world; // package declaration, must ... Compile/Run: C:\tmp>javac hello\world\HelloWorld.java C:\tmp... Since the class is not public (package access), the name of the Java file could be anything! If a package access class has a public static void main(String[]) method, it may still be run from the command line using the class name. C:\tmp>copy hello\world\HelloWorld.java hello\worl...

Starting with JDK1.5, Java allowed variable arguments (varargs) to methods. You use three dots after the final parameter type to indicate that variable number of arguments may be passed. Varargs can only be used in the final argument position. For example: static int sum (int ... numbers) { int total... Some examples from the Java API: java.text.MessageFormat: public static String format(String pattern, Object... java.lang.String: public static String format(String format, Object.... java.lang.ProcessBuilder: public ProcessBuilder(String... command)