Eclipse not recognising Java-17 - java

Hi today I installed java 17 and eclipse(with latest version- 2021‑09). But after all configuration it is showing JavaSE-16 as jdk version. I ignored it and started writing a program with sealed classes. Then it is showing an error. I managed to solve the problem by installing the Java-17 support plugin from eclipse marketplace. Is it possible in eclipse without installing anything.

The release notes state this:
Supports Java 17, including Pattern Matching for Switch (Preview),
Sealed Classes, and more via Eclipse Marketplace
That means currently you have to install the plugin, later support will be included.
You might also want to read this: https://www.eclipse.org/eclipse/news/4.21/jdt.php

Install java 17 plugin from this link. Then your likely to have a content assist error. Fix it by this answer.

The support should be official with Eclipse 4.22 (Q4 2021)
Java 17
Java 17 is out and Eclipse JDT supports Java 17 in 4.22.
The release notably includes the following Java 17 features:
JEP 306: Restore Always-Strict Floating-Point Semantics.
JEP 406: Pattern Matching for switch (Preview).
JEP 409: Sealed Classes (Final).
Please note that preview option should be on for preview language features. >For an informal introduction of the support, please refer to J**ava 17 Examples wiki**.

Related

How do I find the most recent version of JavaFX to implement in my build.gradle file?

What I believe is the official website, openjfx.io, tells me to use version 0.0.10 in gradle. However, It's incompatible with JDK 8 and 17, spitting out java.lang.UnsupportedClassVersionError: org/openjfx/gradle/JavaFXPlugin has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0
I looked through the JavaFX repo, but couldnt find a good version number to replace 0.0.10 with, but I don't think 0.0.10 is really the most recent one. Where can I find the most recent build number?
tl;dr
Currently the latest versions for JavaFX development would be:
JavaFX Gradle Plugin 0.0.10 (simplifies working with JavaFX 11+ in Gradle projects)
OpenJFX 17.0.1 (libraries that implement JavaFX, require Java 11 or later)
Java 17.0.1 (an LTS version)
JavaFX Gradle Plugin
Comments by Slaw point out that you seem to be confusing the Gradle plug-in for JavaFX with the OpenJFX libraries needed to run a JavaFX app.
The plug-in simplifies working with JavaFX 11+ for Gradle projects.
Currently, that plugin’s latest version is 0.0.10. See also the GitHub product page.
OpenJFX libraries
As for the OpenJFX libraries, see the Products Roadmap at GluonHQ.com. You will find 17.0.1 is the latest, with 18 in early-access.
The JavaFX (OpenJFX) releases have been synced to arrive at about the same time as the Java releases, and use the same major version number. A convenient approach.
But OpenJFX releases do not require the latest Java. The Release Notes for 17 says it requires Java 11 or later. Note that both Java 11 and 17 are Long-Term Support (LTS) versions.
I suggest you generally do your development work with the latest Java and the latest JavaFX while aiming your deployments at the latest LTS version of both. Note that Oracle recently announced a change in the LTS cadence from every three years to every two years. Presumably JavaFX will follow that as well.
See also the related Question, Which version of OpenJFX (JavaFX) and Scene Builder should I use with Amazon Corretto 11 (OpenJDK)?.

Plugin for Java 15 support in eclipse 2020-09 no longer available

This question is similar to this one. I know you need to have this plugin to support Java 15 in eclipse 2020-09, however, it doesn't seem to be available any longer.
When I try to install it via the marketplace, I am getting this error:
No repository found at
https://download.eclipse.org/eclipse/updates/4.17-P-builds/.
Is there a way to install it from other sources?
I know that eclipse 2020-12 has been released, but we cannot use it due to bug #569498 (which didn't happen in eclipse 2020-09). So we would really need a way to install Java 15 support in eclipse 2020-09.
Because of regressions in 4.18, I decided to recreate 4.17-P-builds repository.
Please note this will be available till 4.19 is released or we decide to create a patch for 4.18 release.
I got a answer from the eclipse forums
Java 15 support is included in eclipse 4.18(2020-12). As part of
cleaning old releases we removed 4.17-P-builds repo as it is not
supported anymore.
Please upgrade to 2020-12 to continue work on java 15

Pentaho Kettle Java 11 Roadmap

Currently Pentaho Kettle (v.9.1) officially only support Java 8. This is a problem for us, since we are maintaining a plugin that needs Java 11 because of a essential library that needs Java 11. Does anyone have details on the roadmap for the migration to Java 11. I could only find some older information that Java 11 is on the roadmap, but not when it will be available for Kettle.
Our current solution is to use Java 11. You can get Spoon running when removing the JAVA_ENDORSED_DIRS from the bat/sh file. But this is not the best solution since the application is not fully compatible and we are experiencing more and more problems.
Also alternative ideas or solutions are welcome.
As of May 20, the README.md of the Pentaho Kettle repository explicitly mentions Java 11, so it seems as if that is now officially supported.

IntelliJ doesn't Understand java libraries on Java9-ea

I am using jdk9-ea 149 and created a sample javafx application
IntelliJ doesn't understand the java libraries, It's shows all the import statement in red color and they are all grayed out.even for java.util.List, java.util.ArrayList it has the same issue.
I am able to compile form outside but i am not able to compile the code from IntelliJ 2016.3.2 Ultimate Edition.
It looks like we need to add some libraries to IntelliJ project but with java9 build 149 jigsaw i don't know how to do that.
I am using Experimental features still it doesn't understand the import statements - see intellij setting below
IntelliJ Version : IntelliJ 2016.3.2 Ultimate Edition
Java Version: java 9-ea build: 149
As mentioned in IntelliJ IDEA 2016.3.1 is Out:
Speaking of JDK 9, IntelliJ IDEA 2016.3 won’t support builds 148 and up because they contain code that breaks things. Of course, we’re working to resolve this, and will support the latest JDK 9 builds in 2017.1 (its EAP may well start within the next few weeks).
In IntelliJ IDEA 2017.1: Java 9, Kotlin 1.1, Spring, Gradle, JavaScript, Go and more it says:
The latest builds of JDK 9 are fully supported, with assisted project import and coding assistance for editing module declarations.
So if you are using Java 9 build 148 or higher, you need to use version 2017.1 or higher.
Alternatively, if you need to use an older version of IntelliJ, downgrade to Java 9 build 147 or lower.
The latest version of IntelliJ IDEA, 2017.1, does support jdk 9.

Java 7 language features with Android

Just wondering if anyone has tried using new Java 7 language features with Android?
I know that Android reads the bytecode that Java spits out and turns it to dex. So I guess my question is can it understand the bytecode of Java 7?
If you are using Android Studio, the Java 7 language should be enabled automatically without any patches. Try-with-resource requires API Level 19+, and NIO 2.0 stuff are missing.
If you can't use Java 7 features, see #Nuno's answer on how to edit your build.gradle.
The following is for historical interest only.
A small part of Java 7 can certainly be used with Android (note: I have only tested on 4.1).
First of all, you could not use Eclipse's ADT because it is hard-coded that only Java compiler 1.5 and 1.6 are compliant. You could recompile ADT but I find there is no simple way to do that aside from recompiling the whole Android together.
But you don't need to use Eclipse. For instance, Android Studio 0.3.2, IntelliJ IDEA CE and other javac-based IDEs supports compiling to Android and you could set the compliance even up to Java 8 with:
File → Project Structure → Modules → (pick the module at the 2nd pane) → Language level → (choose "7.0 - Diamonds, ARM, multi-catch, etc.")
This only allows Java 7 language features, and you can hardly benefit from anything since a half of improvement also comes from the library. Features you could use are those which do not depend on the library:
Diamond operator (<>)
String switch
Multiple-catch (catch (Exc1 | Exc2 e))
Underscore in number literals (1_234_567)
Binary literals (0b1110111)
And these features cannot be used yet:
The try-with-resources statement — because it requires the non-existing interface "java.lang.AutoCloseable" (this can be used publicly in 4.4+)
The #SafeVarargs annotation — because "java.lang.SafeVarargs" does not exist
... "yet" :) It turns out that, although Android's library is targeting for 1.6, the Android source does contain interfaces like AutoCloseable and traditional interfaces like Closeable does inherit from AutoCloseable (SafeVarargs is really missing, though). We could confirm its existence via reflection. They are hidden simply because the Javadoc has the #hide tag, which caused the "android.jar" not to include them.
There is already as existing question How do I build the Android SDK with hidden and internal APIs available? on how to get those methods back. You just need to replace the existing "android.jar" reference of the current Platform with our customized one, then many of the Java 7 APIs will become available (the procedure is similar to that in Eclipse. Check Project Structure → SDKs.)
In additional to AutoCloseable, (only) the following Java 7 library features are also revealed:
Exception chaining constructors in ConcurrentModificationException, LinkageError and AssertionError
The static .compare() methods for primitives: Boolean.compare(), Byte.compare(), Short.compare(), Character.compare(), Integer.compare(), Long.compare().
Currency: .getAvailableCurrencies(), .getDisplayName() (but without .getNumericCode())
BitSet: .previousSetBit(), .previousClearBit(), .valueOf(), .toLongArray(), .toByteArray()
Collections: .emptyEnumeration(), .emptyIterator(), .emptyListIterator()
AutoCloseable
Throwable: .addSuppressed(), .getSuppressed(), and the 4-argument constructor
Character: .compare(), .isSurrogate(), .getName(), .highSurrogate(), .lowSurrogate(), .isBmpCodePoint() (but without .isAlphabetic() and .isIdeographic())
System: .lineSeparator() (undocumented?)
java.lang.reflect.Modifier: .classModifiers(), .constructorModifiers(), .fieldModifiers(), .interfaceModifiers(), .methodModifiers()
NetworkInterface: .getIndex(), .getByIndex()
InetSocketAddress: .getHostString()
InetAddress: .getLoopbackAddress()
Logger: .getGlobal()
ConcurrentLinkedDeque
AbstractQueuedSynchronizer: .hasQueuedPredecessors()
DeflaterOutputStream: the 3 constructors with "syncFlush".
Deflater: .NO_FLUSH, .SYNC_FLUSH, .FULL_FLUSH, .deflate() with 4 arguments
That's basically all. In particular, NIO 2.0 does not exist, and Arrays.asList is still not #SafeVarargs.
EDIT: At the time this was written, the latest release was Android 9 and Eclipse Indigo. Thing have changed since then.
Practical answer
Yes, I have tried. But this is not a great test as the compatibility was limited to level 6 with no way (no simple way at least) to really use java 7:
First I installed a JDK7 on a machine that had no other JDK installed - Eclipse and Android are not installed either:
Then I installed a brand new Eclipse Indigo and checked it was actually using the JDK 7 (well, as this is the only one and as this is the one I've selected I would have been surprised)
Then I installed the latest version of the Android SDK (EDIT: Honeycomb, API13, at the time this post was written). It found my JDK 7 and installed properly. The same for ADT.
But I had a surprise when trying to compile and run a Hello Word Android app. The compatibility was set to Java 6 with no way to force it to Java 7:
I tried with a non-Android project, a regular Java one, and I had the explanation. The compatibility level seems to be limited by Eclipse (see the message at bottom of the following image):
So I had Hello World working, and also other apps, more complicated and using SQLite, Listview, Sensor and Camera, but this only proves that the compatibility handling of Java 7 seems to be well done and working with Android.
So, did someone try with the good old Ant, to bypass the Eclipse limitation seen above?
Theroetical answer
Anyway, the SDK is designed to be used with Java 5 or 6, as explained here.
We may have something working with Java 7, but it would be working "by accident". The building of the DEX may work properly or not, and once the DEX built, it may work or not. This because using a non-qualified JDK gives unpredictable results by definition.
Even if someone has succesfully built an Android app under plain Java 7, this does not qualify the JDK. The same process applied to another application may fail, or the resulting application may have bugs tied to the use of that JDK. Not recommended.
For those who are involved on webapps development, this exactly the same as deploying a web application built under Java 5 or 6 under an application server qualified for Java 4 only (let's say Weblogic 8 for example). This may work, but this is not something that can be recommended for other purposes than trying.
Quote from dalvikvm.com:
dx, included in the Android SDK, transforms the Java Class files of Java classes compiled by a regular Java compiler into another class file format (the .dex format)
That means, the .java source file does not matter, it's only the .class bytecode.
As far as I know, only invokedynamic was added to the JVM bytecode in Java 7, the rest is compatible to Java 6. The Java language itself does not use invokedynamic. Other new features, like the switch statement using Strings or the multi-catch are just syntatic sugar and did not require byte code changes. For example, the multi-catch just copies the catch-block for each possible exception.
The only problem should be that the new classes introduced in Java 7 are missing in Android, like AutoCloseable, so I'm not sure if you can use the try-with-resources feature (somebody tried it?).
Any comments on that? Am I missing something?
As of the Android SDK v15, along with Eclipse 3.7.1, Java 7 is not supported for Android development. Setting the source compatibility to 1.7 mandates setting the generated .class file compatibility to 1.7, which leads to the following error by the Android compiler:
Android requires compiler compliance level 5.0 or 6.0. Found '1.7' instead. Please use Android Tools > Fix Project Properties.
To expand on the above answer by #KennyTM, if you are targeting 4.0.3 and above (minSdkVersion=15), you can use the hidden APIs by adding a few classes to your target's SDK android.jar.
Once you do this, you can use try-with-resources on any Closeable, as well as implement AutoCloseable in your own classes.
I've made a zip containing sources and binaries of all the classes that needed to be modified in android.jar to make these APIs available. You just need to unpack it and add the binaries to your android-sdk/platforms/android-NN/android.jar
You can download it from here: http://db.tt/kLxAYWbr
Also of note is that, in the past couple of months, Elliott Hughes has made a few commits to the Android tree: finished off AutoCloseable, added SafeVarargs, unhidden various APIs, fixed Throwable's protected constructor and added support for version 51 class files in dx. So, there is finally some progress going on.
Edit (April 2014):
With the release of SDK 19 it is no longer necessary to patch android.jar with the additional APIs.
The best method to use try-with-resources in Android Studio for an app that targets 4.0.3 and above (minSdkVersion=15) is add the following compileOptions to your build.gradle:
android {
compileSdkVersion 19
buildToolsVersion '19.0.3'
defaultConfig {
minSdkVersion 15
targetSdkVersion 19
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_7
targetCompatibility JavaVersion.VERSION_1_7
}
}
Android Studio will complain that try-with-resources can't be used with this API level, but my experience is that it can. The project will build and run without issue on devices with 4.0.3 and above. I've experienced no issues with this, with an app that has been installed into 500k+ devices.
To ignore this warning, add the following to your lint.xml:
<issue id="NewApi">
<ignore regexp="Try-with-resources requires API level 19"/>
</issue>
It seems that getting this to work with pure ant is a bit of a kludge.
But it worked for me: http://www.informit.com/articles/article.aspx?p=1966024
In order to use Java 7 features in code build by Android's ant based build system, simply put the following in your custom_rules.xml in your projects root directory:
custom_rules.xml:
<project name="custom_android_rules">
<property name="java.target" value="1.7" />
<property name="java.source" value="1.7" />
</project>
Some people might be interested in this git project I've found, that seems to allow to run Java 7 on android.
https://github.com/yareally/Java7-on-Android
However too much of a risk if I add this in the current project I work on. So I'll wait until Google to officially support Java 7.

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