* **Java source compatibility** is the ability to upgrade Java uses of OkHttp 3.x to 4.x without
   changing `.java` files.

 * **Kotlin source compatibility** is the ability to upgrade Kotlin uses of OkHttp 3.x to 4.x
   without changing `.kt` files.

With a few small exceptions (below), OkHttp 4.x is both binary- and Java source-compatible with

package okhttp3.containers

import assertk.assertThat
import assertk.assertions.contains
import assertk.assertions.isEmpty
import assertk.assertions.isNotEmpty
import java.io.ByteArrayOutputStream
import java.io.PrintStream
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
import okhttp3.Dispatcher
import okhttp3.HttpUrl.Companion.toHttpUrl
import okhttp3.OkHttpClient
import okhttp3.Request

 * limitations under the License.
 */
package okhttp3

import assertk.assertThat
import assertk.assertions.isEqualTo
import assertk.assertions.isNull
import java.io.FileDescriptor
import java.io.FileInputStream
import java.io.IOException
import java.nio.file.Path
import okhttp3.MediaType.Companion.toMediaType
import okhttp3.RequestBody.Companion.asRequestBody
import okhttp3.RequestBody.Companion.toRequestBody

the `Accept-Encoding` header is not otherwise set. Web servers must be configured to return zstd
responses.

Note that zstd is not used for sending requests.

```java
OkHttpClient client = new OkHttpClient.Builder()
  .addInterceptor(ZstdInterceptor.INSTANCE)
  .build();
```

```kotlin
implementation("com.squareup.okhttp3:okhttp-zstd:0.0.0")
```

package okhttp3.internal

import java.io.IOException
import java.io.InterruptedIOException
import java.net.ServerSocket
import java.net.Socket
import java.net.SocketTimeoutException
import java.nio.charset.Charset
import java.util.Collections
import java.util.Locale
import java.util.TimeZone
import java.util.concurrent.ThreadFactory
import java.util.concurrent.TimeUnit
import kotlin.text.Charsets.UTF_16BE

  }, {
    "testId" : "org.gradle.performance.regression.java.JavaConfigurationCachePerformanceTest.assemble loading configuration cache state with cold daemon",
    "groups" : [ {
      "testProject" : "largeJavaMultiProjectNoBuildSrc",
      "coverage" : {
        "per_commit" : [ "linux" ]
      }
    } ]
  }, {

            lock.writeLock().unlock();
        }
    }
}
```

### 4.3 Directory Lease Manager
```java
package jcifs.internal.smb2.lease;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class DirectoryLeaseManager {
    private final CIFSContext context;

set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"

@rem Find java.exe
if defined JAVA_HOME goto findJavaFromJavaHome

set JAVA_EXE=java.exe
%JAVA_EXE% -version >NUL 2>&1
if %ERRORLEVEL% equ 0 goto execute

echo. 1>&2
echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
echo. 1>&2

  fi
fi

if [ -z "$JAVACMD" ] ; then
  if [ -n "$JAVA_HOME"  ] ; then
    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
      # IBM's JDK on AIX uses strange locations for the executables
      JAVACMD="$JAVA_HOME/jre/sh/java"
    else
      JAVACMD="$JAVA_HOME/bin/java"
    fi
  else
    JAVACMD="`which java`"
  fi
fi

if [ ! -x "$JAVACMD" ] ; then
  echo "Error: JAVA_HOME is not defined correctly." >&2

import assertk.assertions.containsExactly
import assertk.assertions.hasMessage
import assertk.assertions.isEqualTo
import assertk.assertions.isIn
import java.io.IOException
import java.net.InetSocketAddress
import java.net.UnknownHostException
import java.time.Duration
import java.util.Arrays
import java.util.concurrent.TimeUnit
import kotlin.test.assertFailsWith
import mockwebserver3.MockResponse
import mockwebserver3.MockWebServer