Motivation:
How we init our static fields in Conscrypt was kind of error-prone and may even lead to NPE later on when methods were invoked out of order.
Modifications:
- Move all the init code to a static block
- Remove static field which is not needed anymore
Result:
Cleanup and also fixes https://github.com/netty/netty/issues/10413
Motiviation:
When TLSv1.3 was introduced almost 2 years ago, it was decided to disable it by default, even when it's supported by the underlying TLS implementation.
TLSv13 is pretty stable now in Java (out of the box in Java 11, OpenJSSE for Java 8, BoringSSL and OpenSSL) and may be enabled by default.
Modifications:
Ensure TLSv13 is enabled by default when the underyling JDK SSLEngine implementation enables it as well
Result:
TLSv1.3 is now enabled by default, so users don't have to explicitly enable it.
Co-authored-by: Stephane Landelle <slandelle@gatling.io>
Motivation:
AlgorithmId.sha256WithRSAEncryption_oid was removed in JDK15 and later so we should not depend on it as otherwise we will see compilation errors
Modifications:
Replace AlgorithmId.sha256WithRSAEncryption_oid usage with specify the OID directly
Result:
Compiles on JDK15+
Motivation:
Replace Class.getClassLoader with io.netty.util.internal.PlatformDependent.getClassLoader in Openssl so it also works when a SecurityManager is in place
Modification:
Replace Class.getClassLoader with io.netty.util.internal.PlatformDependent.getClassLoader in Openssl
Result:
No issues when a SecurityManager is in place
Motivation:
TLSv1.3 is not strictly limited to Java11+ anymore as different vendors backported TLSv1.3 to Java8 as well. We should ensure we make the detection of if TLSv1.3 is supported not depend on the Java version that is used.
Modifications:
- Add SslProvider.isTlsv13Supported(...) and use it in tests to detect if we should run tests against TLSv1.3 as well
- Adjust testcase to work on latest JDK 8 release as well
Result:
Correct detection of TLSv1.3 support even if Java version < 11.
Motivation:
At the moment we don't support session caching for client side when using native SSLEngine implementation and our implementation of SSLSessionContext is incomplete.
Modification:
- Consume netty-tcnative changes to be able to cache session in an external cache
- Add and adjust unit tests to test session caching
- Add an in memory session cache that is hooked into native SSLEngine
Result:
Support session caching on the client and server side
Motivation:
jdk.tls.client.enableSessionTicketExtension property must be respect by OPENSSL and OPENSSL_REFCNT SslProvider to ensure a consistent behavior. Due a bug this was not the case and it only worked for OPENSSL_REFCNT but not for OPENSSL.
Modifications:
Move the property check into static method that is used by both
Result:
Correctly respect jdk.tls.client.enableSessionTicketExtension
Motivation:
At the moment we may report BUFFER_OVERFLOW when wrap(...) fails to consume data but still prodce some. This is not correct and we should better report NEED_WRAP as we already have produced some data (for example tickets). This way the user will try again without increasing the buffer size which is more correct and may reduce the number of allocations
Modifications:
Return NEED_WRAP when we produced some data but not consumed any.
Result:
Fix ReferenceCountedOpenSslEngine.wrap(...) state machine
**Motivation:**
We are interested in building Netty libraries with Ahead-of-time compilation with GraalVM. We saw there was [prior work done on this](https://github.com/netty/netty/search?q=graalvm&unscoped_q=graalvm). We want to introduce a change which will unblock GraalVM support for applications using netty and `netty-tcnative`.
This solves the error [that some others encounter](https://github.com/oracle/graal/search?q=UnsatisfiedLinkError+sslOpCipherServerPreference&type=Issues):
```
Exception in thread "main" java.lang.UnsatisfiedLinkError: io.grpc.netty.shaded.io.netty.internal.tcnative.NativeStaticallyReferencedJniMethods.sslOpCipherServerPreference()I [symbol: Java_io_grpc_netty_shaded_io_netty_internal_tcnative_NativeStaticallyReferencedJniMethods_sslOpCipherServerPreference or Java_io_grpc_netty_shaded_io_netty_internal_tcnative_NativeStaticallyReferencedJniMethods_sslOpCipherServerPreference__]
```
**Modification:**
The root cause of the issue is that in the tcnative libraries, the [`SSL.java` class](783a8b6b69/openssl-dynamic/src/main/java/io/netty/internal/tcnative/SSL.java (L67)) references a native call in the static initialization of the class - the method `sslOpCipherServerPreference()` on line 67 is used to initialize the static variable. But you see that `OpenSsl` also uses[ `SSL.class` to check if `netty-tcnative` is on the classpath before loading the native library](cbe238a95b/handler/src/main/java/io/netty/handler/ssl/OpenSsl.java (L123)).
So this is the problem because in ahead-of-time compilation, when it references the SSL class, it will try to load those static initializers and make the native library call, but it cannot do so because the native library has not been loaded yet since the `SSL` class is being referenced to check if the library should be loaded in the first place.
**Solution:** So the proposed solution here is to just choose a different class in the `tcnative` package which does not make a native library call during static initialization. I just chose `SSLContext` if this is OK.
This should have no negative effects other than unblocking the GraalVM use-case.
**Result:**
It fixes the unsatisfied link error. It will fix error for future users; it is a common error people encounter.
Motivation:
BoringSSL behaves differently then OpenSSL and not include any TLS1.3 ciphers in the returned array when calling SSL_get_ciphers(...). This is due the fact that it also not allow to explicit configure which are supported and which not for TLS1.3. To mimic the behaviour expected by the SSLEngine API we should workaround this.
Modifications:
- Add a unit test that verifies enabled protocols / ciphers
- Add special handling for BoringSSL and tls1.3
Result:
Make behaviour consistent
Motivation:
We did not correctly preserve the original cause of the SSLException when all the following are true:
* SSL_read failed
* handshake was finished
* some outbound data was produced durigin SSL_read (for example ssl alert) that needs to be picked up by wrap(...)
Modifications:
Ensure we correctly preserve the original cause of the SSLException and rethrow it once we produced all data via wrap(...)
Result:
Be able to understand why we see an error in all cases
Motivation:
When ApplicationProtocolNegotiationHandler is in the pipeline we should expect that its handshakeFailure(...) method will be able to completly handle the handshake error. At the moment this is not the case as it only handled SslHandshakeCompletionEvent but not the exceptionCaught(...) that is also triggered in this case
Modifications:
- Call handshakeFailure(...) in exceptionCaught and so fix double notification.
- Add testcases
Result:
Fixes https://github.com/netty/netty/issues/10342
The current FLowControlHandler keeps a flag to track whether a read() call is pending.
This could lead to a scenario where you call read multiple times when the queue is empty,
and when the FlowControlHandler Queue starts getting messages, channelRead will be fired only once,
when we should've fired x many times, once for each time the handlers downstream called read().
Modifications:
Minor change to replace the boolean flag with a counter and adding a unit test for this scenario.
Result:
I used TDD, so I wrote the test, made sure it's failing, then updated the code and re-ran the test
to make sure it's successful after the changes.
Co-authored-by: Kareem Ali <kali@localhost.localdomain>
Motivation:
SslHandler currently throws a general SSLException if a wrap attempt
fails due to the SSLEngine being closed. If writes are queued the
failure rational typically requires more investigation to track down the
original failure from a previous event. We may have more informative
rational for the failure and so we should use it.
Modifications:
- SslHandler#wrap to use failure information from the handshake or prior
transport closure if available
Result:
More informative exceptions from SslHandler#wrap if the SSLEngine has
been previously closed.
Motivation:
The `FlowControlHandler` may cache the received messages in a queue in order to do the flow control. However, if this handler is manually removed from pipeline during runtime, those cached messages might not be passed to the next channel handler forever.
Modification:
Dequeue all these cached messages and call `ChannelHandlerContext.fireChannelRead(...)` in `handlerRemoved(...)` method.
Result:
Avoid losing the received messages.
Motivation:
To ensure we not crash in all cases we should better check that the SSL pointer was not freed before using it.
Modifications:
Add missing `isDestroyed()` checks
Result:
Ensure we not crash due usage of freed pointer.
Motivation:
make the existing setter `ReferenceCountedOpenSslContext.setUseTasks` public
Modification:
Added the `public` qualified and removed the comment "for tests only"
Result:
Fixes#10288
Motivation:
We should respect jdk.tls.client.enableSessionTicketExtension and jdk.tls.server.enableSessionTicketExtension when using the native SSL implementation as well to make the usage of it easier and more consistent. These properties were introduced by JDK13:
https://seanjmullan.org/blog/2019/08/05/jdk13
Modifications:
Check if the properties are set to true and if so enable tickets
Result:
Easier to enable tickets and be more consistent
Motivation:
BoringSSL supports to automatically manage the session tickets to be used and so also rotate them etc. This is often prefered by users as it removed some complexity. We should support to make use of this.
Modifications:
- Allow to have setSessionTickets() called without an argument or an empty array
- Add tests
Result:
Easier usage of session tickets
Motivation:
OpenSslSession.getLocalCertificates() and getLocalPrincipal() must return null on client side if mTLS is not used as stated in the API documentation. At the moment this is not always the case
Modifications:
- Ensure we only return non-null if mTLS is used
- Add unit tests
Result:
Follow SSLSession API contract
Motivation:
EC is better than RSA because of the small key size, efficient and secure which makes it perfect for testing purposes.
Modification:
Added support to specify an algorithm (EC or RSA) in constructors for key pair generation. The default key size is 256-bits as promulgated by NSA Suite B.
Result:
Able to generate a self-signed certificate of EC or RSA.
Motivation:
Currently calculateSize method in AbstractTrafficShapingHandler calculates size for object of type ByteBuf or ByteBufHolder. Adding a check for FileRegion, makes it possible to do traffic shaping for FileRegion objects as well
Modification:
Check if object to be sent is of type FileRegion, if yes calculate the size using its count() method.
Co-authored-by: Dinesh Joshi <dinesh.joshi@apple.com>
Motivation:
We need to make some slightly changes to be able to build on Java15 as some previous deprecated methods now throw UnsupportedOperationException
Modifications:
- Add code to handle UnsupportedOperationException
- Revert previous applied workaround for bug that was fixed in Java15
- Add maven profile
Result:
Be able to build with latest Java15 EA release
Motivation:
We should provide more informations when ALPN is not supported and a user tries to use it.
Modifications:
- Use UnsupportedOperationException
Result:
Easier to debug ALPN problems
Motivation:
ALPN support was backported to java 8 lately. Ensure we support it if the user uses the latest java 8 release
Modifications:
- Update logic to be able to detect if ALPN is supported out of the box when using Java8
- Update jetty alpn version
Result:
Be able to use ALPN out of the box when using java 8u251
Motivation:
The `AbstractTrafficShapingHandler` caches the `ReopenReadTimerTask` instance in the channel attribute. However, if this handler is removed from the channel pipeline, this `ReopenReadTimerTask` instance may not be released.
Modification:
Release the channel attribute `REOPEN_TASK` in `handlerRemoved` method.
Result:
Avoid a channel attribute leak.
Motivation:
Only cipher suite is logged during handshake. Picked protocol is interesting too.
Modification:
Log protocol as well.
Result:
More interesting information when debugging TLS handshakes.
**Motivation:**
Following up on https://github.com/netty/netty/issues/10181
I was able to successfully setup a Netty server with TLS on Android, using Conscrypt, with the change proposed here. Conscrypt publishes an [Android specific version](https://github.com/google/conscrypt#android). But the current availability check prevents Netty from using it (the call `PlatformDependent.javaVersion()` returns `6` on Android).
**Modification:**
Check whether the java version is above 8, or if it's running on an Android device, to flag Conscrypt as available (besides the remaining checks).
**Result:**
Netty with TLS runs fine on Android 👍
Motivation:
If the SslHandler is removed from the pipeline we also need to ensure we fail the handshake / close promise if it was not notified before as otherwise we may never do so.
Modifications:
- Correctly fail promise and notify pipeline if handshake was not done yet when the SslHandler is removed
- Add unit test
Result:
Fix https://github.com/netty/netty/issues/10158
Motivation:
Before release 4.1.23, there was only ONE call to exceptionCaught method when an ssl handshake failure occurs, now we have two when using the JDK provider.
Modifications:
- Ensure we only propagate one exception fi we already failed the handshake and channelInactive(...) produce an exception again
- Add unit test
Result:
Fixes https://github.com/netty/netty/issues/10119
Motivation:
In general, we will close the debug log in a product environment. However, logging without external level check may still affect performance as varargs will need to allocate an array.
Modification:
Add log level check simply before logging.
Result:
Improve performance slightly in a product environment.
Motivation:
Often it is useful to be able to detect different sorts of SSL errors that cause the handshake to fail. To make this easier we should throw and explicit exception type for handshake timeouts.
Modifications:
- Add SslHandshakeTimeoutException (which extends SSLHandshakeException) and use it for handshake timeouts
- Adjust testcases
Result:
Easier to detect that handshake failed because of a timeout
Motivation:
We did not correctly account for produced bytes when SSL_write(...) returns -1 in all cases. This could lead to lost data and so a corrupt SSL connection.
Modifications:
- Always ensure we calculate the produced bytes correctly
- Add unit tests
Result:
Fixes https://github.com/netty/netty/issues/10041
Motivation:
Due incorrectly handling of reference count of the clientHello ByteBuf we may overrelease the buffer. This did show up in the log of a test:
11:55:16.595 [main] DEBUG i.n.h.ssl.SslClientHelloHandler - Unexpected client hello packet: 16030100bd010000b90303a74225676d1814ba57faff3b3663656ed05ee9dbb2a4dbb1bb1c32d2ea5fc39e0000000100008c0000001700150000164348415434e380824c45414e434c4f5544e38082434e000b000403000102000a00340032000e000d0019000b000c00180009000a00160017000800060007001400150004000500120013000100020003000f0010001100230000000d0020001e060106020603050105020503040104020403030103020303020102020203000f00010133740000
io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1
at io.netty.util.internal.ReferenceCountUpdater.toLiveRealRefCnt(ReferenceCountUpdater.java:74)
at io.netty.util.internal.ReferenceCountUpdater.release(ReferenceCountUpdater.java:138)
at io.netty.buffer.AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:100)
at io.netty.handler.ssl.SslClientHelloHandler.releaseIfNotNull(SslClientHelloHandler.java:181)
at io.netty.handler.ssl.SslClientHelloHandler.select(SslClientHelloHandler.java:225)
at io.netty.handler.ssl.SslClientHelloHandler.decode(SslClientHelloHandler.java:149)
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:498)
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:437)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:355)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:377)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:363)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)
at io.netty.channel.embedded.EmbeddedChannel.writeInbound(EmbeddedChannel.java:343)
at io.netty.handler.ssl.SniHandlerTest.testNonAsciiServerNameParsing(SniHandlerTest.java:297)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.ExpectException.evaluate(ExpectException.java:19)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Modifications:
Correctly transfer lifetime of buffer and so not over-release it.
Result:
Correctly handle buffer lifecycle and so not swallow the original exception
Motivation:
Sometimes it is useful to do something depending on the Ssl ClientHello (like for example select a SslContext to use). At the moment we only allow to hook into the SNI extension but this is not enough.
Modifications:
Add SslClientHelloHandler which allows to hook into ClientHello messages. This class is now also the super class of AbstractSniHandler
Result:
More flexible processing of SSL handshakes
Motivation:
When SslHandler.finishWrap throws an exception, ensure that the promise and buf is not reused to avoid throwing IllegalArgumentException or IllegalReferenceCountException which causes the original exception to be lost.
Modification:
The change ensures that the values for the promise and bytebuf are nulled before calling finishWrap so that it will not be called again with the same arguments.
Result:
Fixes#9971 .
Co-authored-by: Norman Maurer <norman_maurer@apple.com>
Co-authored-by: Antony T Curtis <atcurtis@gmail.com>
Motivation:
In the PR #9003, the issue #8998 was supposedly solved. But actually the fix only made it so the TrustManager can use the specified keystore type instead of also supporting it in the KeyManagerFactory.
In my environment, we are using PKCS#11 Keys which are then rejected by the PKCS#12 keystore. A PKCS#12 keystore is created since the keystoreType was set to null by the code from the mentioned PR.
Modification:
Do not ignore the keystoreType parameter during the creation of the JdkSslClientContext KeyManagerFactory.
Result:
Fixes#8998.
Motivation
LoggingHandler is a very useful tool for debugging and for tracking the
sequence of events in a pipeline. LoggingHandler also includes the
functionality to log a hex dump of all written and received ByteBufs.
This can be useful for small messages, but for large messages, this can
potentially result in extremely large logs. E.g., a 1 MB payload will
result in over a 1 MB log message being recorded. While LoggingHandler
may only be intended for debugging, this can still be too excessive in
some debugging scenarios.
Modifications
* Create a new ByteBufFormat enum that allows users to specify "SIMPLE"
or "HEX_DUMP" logging for ByteBufs.
* For all constructors that currently accept a LogLevel parameter,
create new overloaded constructors that also accept this enum as a
parameter.
* Continue to record hex dumps by default.
Result
Users will be able to opt out of full hex dump recording, if they wish
to.
Motivation:
At the moment we create a new ChannelFutureListener per chunk when trying to write these to the underlying transport. This can be optimized by replacing the seperate write and flush call with writeAndFlush and only allocate the listener if the future is not complete yet.
Modifications:
- Replace seperate write and flush calls with writeAndFlush
- Only create listener if needed, otherwise execute directly
Result:
Less allocations
Motivation:
At the moment we use an extra field in ChunedWriteHandler to hold the current write. This is not needed and makes sense even more error-prone. We can just peek in the queue.
Modifications:
Use Queue.peek() to keep track of current write
Result:
Less error-prone code
Motivation:
At the moment resolving addresses during connect is done via setting an AddressResolverGroup on the Bootstrap. While this works most of the times as expected sometimes the user want to trigger the connect() from the Channel itself and not via the Bootstrap. For this cases we should provide a ChannelHandler that the user can use that will do the resolution.
Modifications:
Add ResolveAddressHandler and tests
Result:
Be able to resolve addresses without Bootstrap
Motivation
A bug was introduced in #9806 which looks likely to be the cause of
#9919. SniHandler will enter an infinite loop if an SSL record is
received with SSL major version byte != 3 (i.e. something other than TLS
or SSL3.0)
Modifications
- Follow default path as intended for majorVersion != 3 in
AbstractSniHandler#decode(...)
- Add unit test to reproduce the hang
Result
Fixes#9919
Motivation:
When `consolidatedWhenNoReadInProgress` is true, `channel.writeAndFlush (data) .addListener (f-> channel.writeAndFlush (data2))` Will cause data2 to never be flushed.
Because the flush operation will synchronously execute the `channel.writeAndFlush (data2))` in the `listener`, and at this time, since the current execution thread is still an `eventloop`(`executor.inEventLoop()` was true), all handlers will be executed synchronously. At this time, since `nextScheduledFlush` is still not null, the `flush` operation of `data2` will be ignored in `FlushConsolidationHandler#scheduleFlush`.
Modification:
- reset `nextScheduledFlush` before `ctx.flush`
- use `ObjectUtil` to polish code
Result:
Fixes https://github.com/netty/netty/issues/9923
Motivation:
At the moment our AbstractSniHandler makes the assemption that Handshake messages are not fragmented. This is incorrect as it is completely valid to split these across multiple TLSPlaintext records.
Thanks to @sskrobotov for bringing this to my attentation and to @Lukasa for the help.
Modifications:
- Adjust logic in AbstractSniHandler to handle fragmentation
- Add unit tests
Result:
Correctly handle fragmented Handshake message in AbstractSniHandler (and so SniHandler).
Motivation:
This is a PR to solve the problem described here: https://github.com/netty/netty/issues/9767
Basically this PR is to add two more APIs in SslContextBuilder, for users to directly specify
the KeyManager or TrustManager they want to use when building SslContext. This is very helpful
when users want to pass in some customized implementation of KeyManager or TrustManager.
Modification:
This PR takes the first approach in here:
https://github.com/netty/netty/issues/9767#issuecomment-551927994 (comment)
which is to immediately convert the managers into factories and let factories continue to pass
through Netty.
1. Add in SslContextBuilder the two APIs mentioned above
2. Create a KeyManagerFactoryWrapper and a TrustManagerFactoryWrapper, which take a KeyManager
and a TrustManager respectively. These are two simple wrappers that do the conversion from
XXXManager class to XXXManagerFactory class
3.Create a SimpleKeyManagerFactory class(and internally X509KeyManagerWrapper for compatibility),
which hides the unnecessary details such as KeyManagerFactorySpi. This serves the similar
functionalities with SimpleTrustManagerFactory, which was already inside Netty.
Result:
Easier usage.
Motivation:
MINIMAL_WAIT is the key constant. Thus, When we see the constant, we must read more code logic to see if it is ms or ns. So improving java doc will be better.
Modifications:
Improve java doc by add "10ms" such as DEFAULT_CHECK_INTERVAL with "1s".
Result:
Easy to know it is ms and keep same java doc style with other constants such as DEFAULT_CHECK_INTERVAL.
Motivation:
Unify parameter validation's code style.
Modifications:
Change the parameter's validation statements to the method: ObjectUtil.checkNotNull.
Result:
The parameter's validation code will keep same style with other codes
