├── .gitignore
├── .idea
    └── androidDexCompiler.xml
├── AndroidManifest.xml
├── Java7-on-Android.iml
├── LICENSE
├── README.md
├── build.xml
├── building_with_ant
├── imgs
    ├── add-depend.png
    ├── addaslib.png
    ├── core-libs.png
    ├── corejar.png
    ├── lang-level.png
    └── sdk-settings.png
├── libs
    └── core.jar
├── project.properties
├── res
    ├── drawable-hdpi
    │   └── ic_launcher.png
    ├── drawable-ldpi
    │   └── ic_launcher.png
    ├── drawable-mdpi
    │   └── ic_launcher.png
    ├── drawable-xhdpi
    │   └── ic_launcher.png
    ├── layout
    │   └── main.xml
    └── values
    │   └── strings.xml
└── src
    └── cc
        └── TestActivity.java


/.gitignore:
--------------------------------------------------------------------------------
1 | gen
2 | 


--------------------------------------------------------------------------------
/.idea/androidDexCompiler.xml:
--------------------------------------------------------------------------------
1 | <?xml version="1.0" encoding="UTF-8"?>
2 | <project version="4">
3 |   <component name="AndroidDexCompilerConfiguration">
4 |     <option name="CORE_LIBRARY" value="true" />
5 |   </component>
6 | </project>
7 | 
8 | 


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/AndroidManifest.xml:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0" encoding="utf-8"?>
 2 | <manifest xmlns:android="http://schemas.android.com/apk/res/android"
 3 |     package="cc.test"
 4 |     android:versionCode="1"
 5 |     android:versionName="1.0">
 6 |     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 7 |     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
 8 |     <uses-sdk android:targetSdkVersion="17"  android:minSdkVersion="8" />
 9 |     <application
10 |         android:label="@string/app_name"
11 |         android:icon="@drawable/ic_launcher">
12 |         <activity
13 |             android:name="cc.TestActivity"
14 |             android:label="@string/app_name">
15 |             <intent-filter>
16 |                 <action android:name="android.intent.action.MAIN" />
17 |                 <category android:name="android.intent.category.LAUNCHER" />
18 |             </intent-filter>
19 |         </activity>
20 |     </application>
21 | </manifest>
22 | 


--------------------------------------------------------------------------------
/Java7-on-Android.iml:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <module type="JAVA_MODULE" version="4">
 3 |   <component name="DBNavigator.Module.ConnectionManager">
 4 |     <connections />
 5 |   </component>
 6 |   <component name="FacetManager">
 7 |     <facet type="android" name="Android">
 8 |       <configuration>
 9 |         <option name="UPDATE_PROPERTY_FILES" value="true" />
10 |       </configuration>
11 |     </facet>
12 |   </component>
13 |   <component name="NewModuleRootManager" inherit-compiler-output="true">
14 |     <exclude-output />
15 |     <content url="file://$MODULE_DIR$">
16 |       <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
17 |       <sourceFolder url="file://$MODULE_DIR$/gen" isTestSource="false" />
18 |       <excludeFolder url="file://$MODULE_DIR$/src/cc/io" />
19 |       <excludeFolder url="file://$MODULE_DIR$/src/java" />
20 |       <excludeFolder url="file://$MODULE_DIR$/src/java/lang" />
21 |     </content>
22 |     <orderEntry type="library" name="core" level="project" />
23 |     <orderEntry type="inheritedJdk" />
24 |     <orderEntry type="sourceFolder" forTests="false" />
25 |   </component>
26 | </module>
27 | 
28 | 


--------------------------------------------------------------------------------
/LICENSE:
--------------------------------------------------------------------------------
 1 | Copyright (c) 2012 Wes Lanning, http://codingcreation.com
 2 | 
 3 | Permission is hereby granted, free of charge, to any person obtaining
 4 | a copy of this software and associated documentation files (the
 5 | "Software"), to deal in the Software without restriction, including
 6 | without limitation the rights to use, copy, modify, merge, publish,
 7 | distribute, sublicense, and/or sell copies of the Software, and to
 8 | permit persons to whom the Software is furnished to do so, subject to
 9 | the following conditions:
10 | 
11 | The above copyright notice and this permission notice shall be
12 | included in all copies or substantial portions of the Software.
13 | 
14 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 | NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
18 | LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
19 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
20 | WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 | 
22 | http://www.opensource.org/licenses/mit-license.php


--------------------------------------------------------------------------------
/README.md:
--------------------------------------------------------------------------------
 1 | # Using Java 7 & 8 Features on Android
 2 | 
 3 | Feeling like you're stuck in 2006 while developing apps and libraries for Android?
 4 | 
 5 | Don't worry, you're not alone. However, there's a solution!
 6 | 
 7 | To help bring Android Java development into the modern era, I've tested and compiled a list of Java 7 and 8 features that will work on Android. Some of them, I discovered through a bit of testing and modding, while others depend on libraries maintained by others independently. Without further BS, here's a list of everything that can be used without issues on at least Android 2.2+.
 8 | 
 9 | ## Google Now Officially Supports Java 7 on Android
10 | 
11 | Starting with Android 4.4, [Google has declared officially](http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Using-sourceCompatibility-1.7) that you can use Java 7 features with build-tools version 19. Directions for how to set it up with Gradle can be found on [tools.android.com](http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Using-sourceCompatibility-1.7).
12 | 
13 | 
14 | ## Possible (Working) Features
15 | 
16 | * Try with resources (auto closing file handlers)
17 | * String switches
18 | * Multiple exceptions caught in one catch block
19 | * Integer (and binary) literals for readability
20 | * Type inference on collections (a.k.a. "diamonds")
21 | * [Java 8 lambdas thanks to Orfjackal (instructions coming soon)](https://github.com/orfjackal/retrolambda)
22 | * [Java 7 fork-join via JSR-166 (instructions coming soon)](http://gee.cs.oswego.edu/dl/concurrency-interest/index.html)
23 | 
24 | 
25 | ## Things that don't Work
26 | 
27 | * Java 7 file API (java.nio.*) because some native code needs ported
28 | * File change notifications (watch/notify file api stuff)
29 | * Invoke Dynamic and features that rely on it (would require modifying Dalvik to support it)
30 | 
31 | 
32 | ## Setting up on Intellij IDEA 13 (and probably Android Studio)
33 | 
34 | The new Intellij finally has a built in option to override core libraries of Android, making much of the above far easier. The instructions below take advantage of this and allow us to override the core libraries with a jar within Intellij IDEA normal build process. If using Intellij IDEA 12, you'll have to use the [old fallback instructions](https://github.com/yareally/Java7-on-Android/tree/master) as the directions for Intellij IDEA 13 will not work.
35 | 
36 | 
37 | 1. Clone this project or grab core.jar from the libs directory.
38 | 2. Enable overriding the Android core libraries by going to File → Settings → Compiler → Android Compilers
39 | ![alt text](imgs/core-libs.png "Enable overriding Android core libraries")
40 | 3. Ensure core.jar is in your project library directory like below:
41 | ![alt text](imgs/corejar.png "Put core.jar in the libs directory")
42 | 4. Go to the File dropdown menu → Project Structure → Libraries and create a new library with core.jar:
43 | ![alt text](imgs/addaslib.png "Add core.jar as a library")
44 | 5. While still in the project setup area from above, go to "Modules" and add the newly created library as a project dependency. Ensure that it is placed above the Android SDK so that it overrides the Android SDK when necessary.
45 | ![alt text](imgs/add-depend.png "Add core.jar as a project dependency.")
46 | 6. Under the SDKs settings in the Platform Settings area, ensure you have an Android SDK set up to use at least Java 7 (Java 8 if you wish to use lambdas). Java 8 and Android are a bit quirky together in Intellij, so you may experience issues getting the Java 8 SDK to stick.
47 | ![alt text](imgs/sdk-settings.png "Ensure an Android SDK is using Java 7 or Java 8")
48 | 7. The final setting to change under the project settings area is under "Project." Change the project language level to 7.0 (8.0 if you are going to use lambdas).
49 | ![alt text](imgs/lang-level.png "Add core.jar as a library")
50 | 8. Run this project's Android TestActivity to ensure everything is set up properly. If it does not run or you see syntax errors in Intellij, then ensure you settings looks similar to my screen shots.
51 | 
52 | 
53 | ## FAQ
54 | 
55 | ### Does this really work on stock, unrooted/unmodified Android?
56 | 
57 | Yup, because it's either using syntactic sugar features (which does not modify the bytecode) or it overrides the existing Android libraries.
58 | 
59 | 
60 | ### I'm having a problem unrelated to setting up the above configuration or running the provided example code.
61 | 
62 | If you're having an issue related to either, feel free to file an issue and I will try to help you out when I have a few moments. If you are having an issue pertaining to lambdas or fork-join involving possible bugs in those libraries, please contact the maintainers of each project respectfully.
63 | 
64 | 
65 | ### Can I use Gradle with this?
66 | 
67 | I still have to test it, but it'll probably work as long as you add the jar as a dependency in Gradle instead of under Intellij's build system. Don't forget to [enable the core library](imgs/core-libs.png) setting though. Gradle is also the recommended way to use Java 8 lambdas via [Evant's Gradle plugin](https://github.com/evant/gradle-retrolambda) until I  find a method to do it without Gradle.
68 | 
69 | 
70 | ### Can I use Ant?
71 | 
72 | If you need to use Ant, [I have a guide for that](https://github.com/yareally/Java7-on-Android/blob/master/building_with_ant).
73 | 
74 | 
75 | ### Won't this affect the entire Android System and not just my app?
76 | 
77 | Since every Android app is sandboxed, only your code is affected.
78 | 
79 | 
80 | ### Do you have example code showing things working?
81 | 
82 | Yes, please see the TestActivity included in this project.
83 | 
84 | 
85 | ### Will this work for other resource classes (like ObjectInputStream)?
86 | 
87 | I'm sure it will, I just didn't include them in the jar. See the implemented InputStreams source as a template in the jar. I had to wrap them versus extending due to IDE complaints I was getting (in IDEA 12). Moving them to a separate module might solve that though or IDEA 13 may no longer require that (need to test it).
88 | 
89 | 
90 | ### Why doesn't Google implement these features themselves if they work?
91 | 
92 | I don't work for Google and cannot answer that any better than any other non-employee. Perhaps eventually they will add them, but it's probably more likely they will add official support for a language alternative to Java first.
93 | 
94 | 
95 | ### Will this work on Eclipse/Netbeans/etc?
96 | 
97 | Probably, but I don't really know how Android works on Eclipse/Netbeans, so you're on your own for that. If someone wishes to document the setup process for either, let me know and I will add it here when you're done. Aside from that, Ant works outside of Intellij, but [requires some modifying of the build.xml](https://github.com/yareally/Java7-on-Android/blob/master/building_with_ant) to override some of the compilation time stuff.
98 | 


--------------------------------------------------------------------------------
/build.xml:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <project name="test2" default="help">
 3 | 
 4 |     <!-- The local.properties file is created and updated by the 'android' tool.
 5 |          It contains the path to the SDK. It should *NOT* be checked into
 6 |          Version Control Systems. -->
 7 |     <property file="local.properties" />
 8 | 
 9 |     <!-- The ant.properties file can be created by you. It is only edited by the
10 |          'android' tool to add properties to it.
11 |          This is the place to change some Ant specific build properties.
12 |          Here are some properties you may want to change/update:
13 | 
14 |          source.dir
15 |              The name of the source directory. Default is 'src'.
16 |          out.dir
17 |              The name of the output directory. Default is 'bin'.
18 | 
19 |          For other overridable properties, look at the beginning of the rules
20 |          files in the SDK, at tools/ant/build.xml
21 | 
22 |          Properties related to the SDK location or the project target should
23 |          be updated using the 'android' tool with the 'update' action.
24 | 
25 |          This file is an integral part of the build system for your
26 |          application and should be checked into Version Control Systems.
27 | 
28 |          -->
29 |     <property file="ant.properties" />
30 | 
31 |     <!-- if sdk.dir was not set from one of the property file, then
32 |          get it from the ANDROID_HOME env var.
33 |          This must be done before we load project.properties since
34 |          the proguard config can use sdk.dir -->
35 |     <property environment="env" />
36 |     <condition property="sdk.dir" value="${env.ANDROID_HOME}">
37 |         <isset property="env.ANDROID_HOME" />
38 |     </condition>
39 | 
40 |     <!-- The project.properties file is created and updated by the 'android'
41 |          tool, as well as ADT.
42 | 
43 |          This contains project specific properties such as project target, and library
44 |          dependencies. Lower level build properties are stored in ant.properties
45 |          (or in .classpath for Eclipse projects).
46 | 
47 |          This file is an integral part of the build system for your
48 |          application and should be checked into Version Control Systems. -->
49 |     <loadproperties srcFile="project.properties" />
50 | 
51 |     <!-- quick check on sdk.dir -->
52 |     <fail
53 |         message="sdk.dir is missing. Make sure to generate local.properties using 'android update project' or to inject it through the ANDROID_HOME environment variable."
54 |         unless="sdk.dir" />
55 | 
56 |     <!--
57 |         Import per project custom build rules if present at the root of the project.
58 |         This is the place to put custom intermediary targets such as:
59 |             -pre-build
60 |             -pre-compile
61 |             -post-compile (This is typically used for code obfuscation.
62 |                            Compiled code location: ${out.classes.absolute.dir}
63 |                            If this is not done in place, override ${out.dex.input.absolute.dir})
64 |             -post-package
65 |             -post-build
66 |             -pre-clean
67 |     -->
68 |     <import file="custom_rules.xml" optional="true" />
69 | 
70 |     <!-- Import the actual build file.
71 | 
72 |          To customize existing targets, there are two options:
73 |          - Customize only one target:
74 |              - copy/paste the target into this file, *before* the
75 |                <import> task.
76 |              - customize it to your needs.
77 |          - Customize the whole content of build.xml
78 |              - copy/paste the content of the rules files (minus the top node)
79 |                into this file, replacing the <import> task.
80 |              - customize to your needs.
81 | 
82 |          ***********************
83 |          ****** IMPORTANT ******
84 |          ***********************
85 |          In all cases you must update the value of version-tag below to read 'custom' instead of an integer,
86 |          in order to avoid having your file be overridden by tools such as "android update project"
87 |     -->
88 |     <!-- version-tag: 1 -->
89 |     <import file="${sdk.dir}/tools/ant/build.xml" />
90 | 
91 | </project>
92 | 


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/building_with_ant:
--------------------------------------------------------------------------------
 1 | 1) Go to: /android-sdk-dir/tools/ant/build.xml and open it for editing.
 2 | 
 3 | 2) Change:
 4 | 
 5 | <property name="java.target" value="1.x" />
 6 | <property name="java.source" value="1.x" />
 7 | 
 8 | to:
 9 | 
10 | <property name="java.target" value="1.7" />
11 | <property name="java.source" value="1.7" />
12 | 
13 | 
14 | 3) Rename <macrodef name="dex-helper"> to something like <macrodef name="_dex-helper"> so it uses
15 | the modified one in #4. Commenting it out will probably also work fine.
16 | 
17 | 4) Override dex-helper with this modified macrodef (the important lines are --core-library and --no-strict):
18 | 
19 |     <macrodef name="dex-helper">
20 |        <element name="external-libs" optional="yes" />
21 |        <element name="extra-parameters" optional="yes" />
22 |        <sequential>
23 |             <!-- sets the primary input for dex. If a pre-dex task sets it to
24 |                  something else this has no effect -->
25 |             <property name="out.dex.input.absolute.dir" value="${out.classes.absolute.dir}" />
26 |             <!-- set the secondary dx input: the project (and library) jar files
27 |                  If a pre-dex task sets it to something else this has no effect -->
28 |             <if>
29 |                 <condition>
30 |                     <isreference refid="out.dex.jar.input.ref" />
31 |                 </condition>
32 |                 <else>
33 |                     <path id="out.dex.jar.input.ref">
34 |                         <path refid="project.all.jars.path" />
35 |                     </path>
36 |                 </else>
37 |             </if>
38 |          <apply executable="${dx}" failonerror="true" parallel="true">
39 |              <arg value="--dex" />
40 |              <arg value="--core-library" />
41 |              <arg value="--no-locals" />
42 |              <arg value="--verbose" />
43 |              <arg value="--output=${intermediate.dex.file}" />
44 |              <arg value="--no-strict" />
45 |              <extra-parameters />
46 |              <arg path="${out.dex.input.absolute.dir}" />
47 |              <path refid="out.dex.jar.input.ref" />
48 |              <external-libs />
49 |          </apply>
50 |        </sequential>
51 |     </macrodef>
52 | 
53 | 5) add the following path above the <javac encoding="${java.encoding}" tag:
54 | 
55 | <path id="project.bootpath">
56 |    <pathelement location="libs/core.jar" />
57 |    <path refid="project.target.class.path" />
58 | </path>
59 | 
60 | This will point to your project library so you can use the modded files as a jar.
61 | Make sure to name your jar file whatever you named it above (core.jar for this example).
62 | This file will go in your project_dir/libs directory.
63 | 
64 | 6) Inside of <javac encoding="${java.encoding}", change
65 | 
66 | bootclasspathref="project.target.class.path"
67 | 
68 | to: bootclasspathref="project.bootpath"
69 | 
70 | 
71 | 7) Save the file and run ant as normal.
72 | 


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/imgs/add-depend.png:
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/imgs/addaslib.png:
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/imgs/corejar.png:
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/imgs/lang-level.png:
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/imgs/sdk-settings.png:
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/libs/core.jar:
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https://raw.githubusercontent.com/yareally/Java7-on-Android/3df222f53eb881fd041f875ffff407e7df81180a/libs/core.jar


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/project.properties:
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 1 | # This file is automatically generated by Android Tools.
 2 | # Do not modify this file -- YOUR CHANGES WILL BE ERASED!
 3 | #
 4 | # This file must be checked in Version Control Systems.
 5 | #
 6 | # To customize properties used by the Ant build system edit
 7 | # "ant.properties", and override values to adapt the script to your
 8 | # project structure.
 9 | #
10 | # To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):
11 | #proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
12 | 
13 | android.library=false
14 | # Project target.
15 | target=android-18
16 | -source 1.8
17 | -target 1.8


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/res/drawable-hdpi/ic_launcher.png:
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/res/drawable-ldpi/ic_launcher.png:
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/res/layout/main.xml:
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 1 | <?xml version="1.0" encoding="utf-8"?>
 2 | <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3 |     android:orientation="vertical"
 4 |     android:layout_width="fill_parent"
 5 |     android:layout_height="fill_parent">
 6 | 
 7 |     <TextView
 8 |         android:layout_width="fill_parent"
 9 |         android:layout_height="wrap_content"
10 |         android:text="Hello World, TestActivity" />
11 | </LinearLayout>
12 | 
13 | 


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/res/values/strings.xml:
--------------------------------------------------------------------------------
1 | <?xml version="1.0" encoding="utf-8"?>
2 | <resources>
3 |     <string name="app_name">test2</string>
4 | </resources>
5 | 


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/src/cc/TestActivity.java:
--------------------------------------------------------------------------------
  1 | /*
  2 | Copyright (c) 2012 Wes Lanning, http://codingcreation.com
  3 | 
  4 | Permission is hereby granted, free of charge, to any person obtaining
  5 | a copy of this software and associated documentation files (the
  6 | "Software"), to deal in the Software without restriction, including
  7 | without limitation the rights to use, copy, modify, merge, publish,
  8 | distribute, sublicense, and/or sell copies of the Software, and to
  9 | permit persons to whom the Software is furnished to do so, subject to
 10 | the following conditions:
 11 | 
 12 | The above copyright notice and this permission notice shall be
 13 | included in all copies or substantial portions of the Software.
 14 | 
 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 16 | EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 17 | MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 18 | NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 19 | LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 20 | OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 21 | WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 22 | 
 23 | http://www.opensource.org/licenses/mit-license.php
 24 | */
 25 | 
 26 | package cc;
 27 | 
 28 | import android.app.Activity;
 29 | import android.os.Bundle;
 30 | import android.widget.Toast;
 31 | import cc.io._BufferedInputStream;
 32 | import cc.io._FileInputStream;
 33 | import cc.io._FileOutputStream;
 34 | import cc.test.R;
 35 | 
 36 | import java.io.IOException;
 37 | import java.lang.reflect.Method;
 38 | import java.util.ArrayList;
 39 | import java.util.Arrays;
 40 | import java.util.List;
 41 | 
 42 | public class TestActivity extends Activity
 43 | {
 44 |     /**
 45 |      * Called when the activity is first created.
 46 |      */
 47 |     @Override
 48 |     public void onCreate(Bundle savedInstanceState)
 49 |     {
 50 |         super.onCreate(savedInstanceState);
 51 |         setContentView(R.layout.main);
 52 | 
 53 |         try {
 54 |             // obviously does not exist so our exception will be caught.
 55 |             Method multiCatchTest = getClass().getDeclaredMethod("doesNotExist");
 56 |         } catch (SecurityException | NoSuchMethodException | IllegalArgumentException e) {
 57 |             Toast.makeText(this,
 58 |                 "Multicatch exception was caught, yay",
 59 |                 Toast.LENGTH_LONG).show();
 60 |         }
 61 | 
 62 | 
 63 |         /* Java 8 won't work... */
 64 | /*        Runnable r2 = () -> {
 65 |             System.out.println("Second runnable");
 66 |         };
 67 |         r2.run();*/
 68 | /*        Comparator<Integer> cmp = (x, y) -> (x < y) ? -1 : ((x > y) ? 1 : 0);
 69 | 
 70 |         if (cmp.compare(1, 2) == -1) {
 71 |             Toast.makeText(this, "1 is less than 2", Toast.LENGTH_LONG).show();
 72 |         }*/
 73 | 
 74 | 
 75 |         String[] months = {
 76 |             "JAN",
 77 |             "FEB",
 78 |             "MAR",
 79 |             "APR",
 80 |             "MAY",
 81 |             "JUN",
 82 |             "JUL",
 83 |             "AUG",
 84 |             "SEP",
 85 |             "OCT",
 86 |             "NOV",
 87 |             "DEC"};
 88 | 
 89 |         int m = getRandomMonth(12);
 90 | 
 91 |         Toast.makeText(this,
 92 |             String.format(
 93 |                 "%s has %d days in its month.",
 94 |                 months[m],
 95 |                 getDaysInMonth(months[m])),
 96 |             Toast.LENGTH_LONG).show();
 97 | 
 98 |         // showing "try with resources"
 99 |         try (_FileOutputStream fos = new _FileOutputStream("/sdcard/testfile.txt")) {
100 |             // integer literals work, yay
101 |             Toast.makeText(this,
102 |                 String.format(
103 |                     "Shown as 1_000 and 2_000 in the IDE, but shown as %d %d in Android as they should",
104 |                     1_000, 2_000),
105 |                 Toast.LENGTH_LONG).show();
106 | 
107 |             // binary literal also works
108 |             byte[] writeData = {
109 |                 (byte) 0b0101_1110, (byte) 0b1000_0000
110 |             };
111 | 
112 |             fos.write(writeData);
113 |             Toast.makeText(this,
114 |                 String.format(
115 |                     "Written to testfile.txt: %s",
116 |                     Arrays.toString(writeData)),
117 |                 Toast.LENGTH_LONG).show();
118 |         } catch (IOException ioe) {
119 |             Toast.makeText(this,
120 |                 String.format(
121 |                     "Error: %s",
122 |                     ioe.getMessage()),
123 |                 Toast.LENGTH_LONG).show();
124 |         }
125 | 
126 |         try (_BufferedInputStream fis = new _BufferedInputStream( new _FileInputStream("/sdcard/testfile.txt"))) {
127 |             // to show "diamonds" working
128 |             List<String> readData = new ArrayList<>(4);
129 |             int nextInt;
130 | 
131 |             while ((nextInt = fis.read()) != -1) {
132 |                 readData.add(String.valueOf(nextInt));
133 |             }
134 | 
135 |             Toast.makeText(
136 |                 this,
137 |                 String.format(
138 |                     "Read data from testfile.txt: %s",
139 |                     readData.toString()),
140 |                 Toast.LENGTH_LONG).show();
141 |         } catch (IOException ioe) {
142 |             Toast.makeText(this,
143 |                 String.format(
144 |                     "Error: %s",
145 |                     ioe.getMessage()),
146 |                 Toast.LENGTH_LONG).show();
147 |         }
148 |     }
149 | 
150 |     /**
151 |      * Demonstrates that string switches are working.
152 |      *
153 |      * @param month
154 |      * @return
155 |      */
156 |     public static int getDaysInMonth(String month)
157 |     {
158 |         switch (month) {
159 |             case "JAN":
160 |                 return 31;
161 |             case "FEB":
162 |                 return 28;
163 |             case "MAR":
164 |                 return 31;
165 |             case "APR":
166 |                 return 30;
167 |             case "MAY":
168 |                 return 31;
169 |             case "JUN":
170 |                 return 30;
171 |             case "JUL":
172 |             case "AUG":
173 |                 return 31;
174 |             case "SEP":
175 |                 return 30;
176 |             case "OCT":
177 |                 return 31;
178 |             case "NOV":
179 |                 return 30;
180 |             case "DEC":
181 |                 return 31;
182 |             default:
183 |                 return 0;
184 |         }
185 |     }
186 | 
187 |     public static int getRandomMonth(int limit)
188 |     {
189 |         return (int) (Math.random() * limit);
190 |     }
191 | }
192 | 


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