This is a list of built-in Android permission values: Permission Description Since API Level android.permission.ACCESS_CHECKIN_PROPERTIES Allows read/write access to the "properties" table in the checkin database, to change values that get uploaded. 1 android.permission.ACCESS_COARSE_LOCATION Allows an application to access coarse (e.g., Cell-ID, WiFi) location 1 android.permission.ACCESS_FINE_LOCATION Allows an application to access fine (e.g., GPS) location 1 android.permission.ACCESS_LOCATION_EXTRA_COMMANDS Allows an application to access extra location provider commands 1 android.permission.ACCESS_MOCK_LOCATION Allows an application to create mock location providers for testing 1 android.permission.ACCESS_NETWORK_STATE Allows applications to access information about networks 1 android.permission.ACCESS_SURFACE_FLINGER Allows an application to use SurfaceFlinger's low level features 1 android.permission.ACCESS_WIFI_STATE Allows applications to access information about Wi-Fi networks 1 android.permission.ACCOUNT_MANAGER Allows applications to call into AccountAuthenticators. Only the system can get this permission. 5 android.permission.AUTHENTICATE_ACCOUNTS...

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...

There's no such thing as an immutable byte array in Java. What we are trying to achieve here is to protect the byte array inside the object from which it is being returned. We want to caller to have the contents of the byte array, but not be able to change the contents inside the object. The trick is to return a copy instead of the internal reference: public class ReturnByteArray { public stati...

This is a more generic version, which can be expanded to accommodate additional file signatures. import java.io.*; import java.util.*; pu...

This is an example of using java.beans.XMLEncoder and java.beans.XMLDecoder to serialize/deserialize Java objects to XML. Java code TestXMLEncoder.java: import java.io.*; import java.beans.XMLEncoder;... SimpleBean.java: public class SimpleBean { private String na... CompositeBean.java: public class CompositeBean { private Simple... NotABean.java: public class NotABean { private String name... Test Output By default, only Java beans can be serialized using XMLEncoder . Exception occurs when you try to deserialize an object which is not a Java bean. Errors actually occur when you try to serialize, but they are ignored. As a result, an XML file is generated by the serialization but the file is useless! Console output: C:\>java TestXMLEncoder Testing simple bean ... simplebean.xml: <?xml version="1.0" encoding="UTF-8"?> <java v... compositebean.xml: <?xml version="1.0" encoding="UTF-8"?> <java v... nodefault.xml: <?xml version="1.0" encoding="UTF-8"?> <java v......

Parsing XML in Java is really simple: import java.io.*; import javax.xml.parsers.Docu... The parser implementation details are hidden behind the JAXP API. In case you want to know which parser implementation is used, this is what the JavaDoc for DocumentBuilderFactory.newInstance says: Use the javax.xml.parsers.DocumentBuilderFactory system property. Use the properties file " lib/jaxp.properties " in the JRE directory. This configuration file is in standard java.util.Properties format and contains the fully qualified name of the implementation class with the key being the system property defined above. The jaxp.properties file is read only once by the JAXP implementation and it's values are then cached for future use. If the file does not exist when the first attempt is made to read from it, no further attempts are made to...

Create a startup script for inetd Copy /etc/init.d/skeleton to /etc/init.d/inetd . Change the top section of the script to read: PATH=/usr/sbin:/usr/bin:/sbin:/bin DESC="In... Now inetd can be stopped/started/restarted like this: sudo /etc/init.d/inetd stop sudo /etc/init.... Add links to rc*.d $ sudo update-rc.d inetd defaults Adding sy... If you no longer need to start inetd at boot up: $ sudo update-rc.d -f inetd remove update-r... This would remove the links from the start up sequence but leave /etc/init.d/inetd in place. Contents of /etc/init.d/skeleton : #! /bin/sh ### BEGIN INIT INFO # Provide...

From http://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html . There are 6 scopes available: compile : This is the default scope, used if none is specified. Compile dependencies are available in all classpaths of a project. Furthermore, those dependencies are propagated to dependent projects. provided : This is much like compile , but indicates you expect the JDK or a container to provide the dependency at runtime. For example, when building a web application for the Java Enterprise Edition, you would set the dependency on the Servlet API and related Java EE APIs to scope provided because the web container provides those classes. This scope is only available on the compilation and test classpath, and is not transitive. runtime : This scope indicates that the dependency is not required for compilation,...

In java.lang.String , the replace method either takes a pair of char 's or a pair of CharSequence 's (of which String is a subclass, so it'll happily take a pair of String 's). The replace method will replace all occurrences of a char or CharSequence . On the other hand, both String arguments to replaceFirst and replaceAll are regular expressions (regex). Using the wrong function can lead to subtle bugs. public class Test { public static void mai...

This example demonstrates the general steps in creating a custom Java class loader. Normally a class loader would consult its parent class loader when asked to load a class. If it's not loaded by the parent class loader, then the class loader would try to load the class on its own. This class loader tries to load the requested class on its own first, and delegates to the parent only when a java.lang.SecurityException is thrown (which happens when it tries to load core Java classes such as java.lang.String ). The classes are loaded from CLASSPATH through the getResourceAsStream call. It's important to note that when a class is loaded with a certain class loader, all classes referenced from that class are also loaded through the...

The @Retention meta-annotation (annotations to annotate an Annotation Type) can have three values: RetentionPolicy.SOURCE - the annotation is source level, it's ignored by the compiler. RetentionPolicy.CLASS - the annotation is retained at compile time, but ignored by the VM at runtime ( this is the default ) RetentionPolicy.RUNTIME - the annotation is retained at runtime, you can use Java reflection to query the annotation For example: import java.lang.annotation.*; // if @Target is... At runtime, a program can query the annotations through the java.lang.reflect.AnnotatedElement interface, which is implemented by java.lang.Class , java.lang.reflect.Constructor , java.lang.reflect.Field and java.lang.reflect.Method , among others. This is an example from Sun : import java.lang.reflect.*; public clas...