Errors at startup in read-only filesystems environment

### Describe the bug

Hello folks,

After upgrading from 2.21.0 to 2.22.0 (and 2.23.0), when using the java agent, we get errors at startup because we run in an environment where the filesystem is read-only by default:

```
[otel.javaagent 2025-12-16 10:35:09:991 +0000] [main] INFO io.opentelemetry.javaagent.tooling.VersionLogger - opentelemetry-javaagent - version: 2.23.0
[otel.javaagent 2025-12-16 10:35:17:060 +0000] [main] ERROR io.opentelemetry.javaagent.tooling.HelperInjector - Error preparing helpers while processing class java.util.logging.Logger for java-util-logging. Failed to inject helper classes into instance <bootstrap>
java.lang.IllegalStateException: Failed to create temporary directory.
	at io.opentelemetry.javaagent.tooling.HelperInjector.createTempDir(HelperInjector.java:430)
	at io.opentelemetry.javaagent.tooling.HelperInjector.injectBootstrapClassLoader(HelperInjector.java:414)
	at io.opentelemetry.javaagent.tooling.HelperInjector.injectHelperClasses(HelperInjector.java:291)
	at io.opentelemetry.javaagent.tooling.HelperInjector.lambda$transform$11(HelperInjector.java:201)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.AbstractWeakConcurrentMap.lambda$computeIfAbsent$0(AbstractWeakConcurrentMap.java:187)
	at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(Unknown Source)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.AbstractWeakConcurrentMap.computeIfAbsent(AbstractWeakConcurrentMap.java:186)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.WeakConcurrentMap.computeIfAbsent(WeakConcurrentMap.java:48)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.WeakConcurrentMap$WithInlinedExpunction.computeIfAbsent(WeakConcurrentMap.java:221)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.WeakLockFreeCache.computeIfAbsent(WeakLockFreeCache.java:22)
	at io.opentelemetry.javaagent.tooling.HelperInjector.transform(HelperInjector.java:174)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.doTransform(AgentBuilder.java:12822)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.transform(AgentBuilder.java:12759)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.access$1800(AgentBuilder.java:12468)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$Java9CapableVmDispatcher.run(AgentBuilder.java:13250)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$Java9CapableVmDispatcher.run(AgentBuilder.java:13180)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.doPrivileged(AgentBuilder.java)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.transform(AgentBuilder.java:12702)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$ByteBuddy$ModuleSupport.transform(Unknown Source)
	at java.instrument/sun.instrument.TransformerManager.transform(Unknown Source)
	at java.instrument/sun.instrument.InstrumentationImpl.transform(Unknown Source)
	at java.base/java.lang.ClassLoader.findBootstrapClass(Native Method)
	at java.base/java.lang.ClassLoader.findBootstrapClassOrNull(Unknown Source)
	at java.base/java.lang.System$1.findBootstrapClassOrNull(Unknown Source)
	at java.base/jdk.internal.loader.ClassLoaders$BootClassLoader.loadClassOrNull(Unknown Source)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(Unknown Source)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(Unknown Source)
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(Unknown Source)
	at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
	at org.slf4j.bridge.SLF4JBridgeHandler.<clinit>(SLF4JBridgeHandler.java:111)
	at play.api.libs.logback.LogbackLoggerConfigurator.configure(LogbackLoggerConfigurator.scala:91)
	at play.api.libs.logback.LogbackLoggerConfigurator.configure(LogbackLoggerConfigurator.scala:75)
	at play.api.inject.guice.GuiceApplicationBuilder.$anonfun$configureLoggerFactory$1(GuiceApplicationBuilder.scala:158)
	at scala.Option.map(Option.scala:242)
	at play.api.inject.guice.GuiceApplicationBuilder.configureLoggerFactory(GuiceApplicationBuilder.scala:157)
	at play.api.inject.guice.GuiceApplicationBuilder.applicationModule(GuiceApplicationBuilder.scala:116)
	at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:200)
	at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:176)
	at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21)
	at play.core.server.ProdServerStart$.start(ProdServerStart.scala:52)
	at play.core.server.ProdServerStart$.main(ProdServerStart.scala:28)
	at play.core.server.ProdServerStart.main(ProdServerStart.scala)
Caused by: java.nio.file.FileSystemException: /tmp/opentelemetry-temp-jars7548131800099795207: Read-only file system
	at java.base/sun.nio.fs.UnixException.translateToIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixFileSystemProvider.createDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createDirectory(Unknown Source)
	at java.base/java.nio.file.TempFileHelper.create(Unknown Source)
	at java.base/java.nio.file.TempFileHelper.createTempDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createTempDirectory(Unknown Source)
	at io.opentelemetry.javaagent.tooling.HelperInjector.createTempDir(HelperInjector.java:428)
	... 42 more
[otel.javaagent 2025-12-16 10:35:17:075 +0000] [main] ERROR io.opentelemetry.javaagent.tooling.HelperInjector - Error preparing helpers while processing class java.util.logging.LogManager$RootLogger for java-util-logging. Failed to inject helper classes into instance <bootstrap>
java.lang.IllegalStateException: Failed to create temporary directory.
	at io.opentelemetry.javaagent.tooling.HelperInjector.createTempDir(HelperInjector.java:430)
	at io.opentelemetry.javaagent.tooling.HelperInjector.injectBootstrapClassLoader(HelperInjector.java:414)
	at io.opentelemetry.javaagent.tooling.HelperInjector.injectHelperClasses(HelperInjector.java:291)
	at io.opentelemetry.javaagent.tooling.HelperInjector.lambda$transform$11(HelperInjector.java:201)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.AbstractWeakConcurrentMap.lambda$computeIfAbsent$0(AbstractWeakConcurrentMap.java:187)
	at java.base/java.util.concurrent.ConcurrentHashMap.computeIfAbsent(Unknown Source)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.AbstractWeakConcurrentMap.computeIfAbsent(AbstractWeakConcurrentMap.java:186)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.WeakConcurrentMap.computeIfAbsent(WeakConcurrentMap.java:48)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.weaklockfree.WeakConcurrentMap$WithInlinedExpunction.computeIfAbsent(WeakConcurrentMap.java:221)
	at io.opentelemetry.javaagent.shaded.instrumentation.api.internal.cache.WeakLockFreeCache.computeIfAbsent(WeakLockFreeCache.java:22)
	at io.opentelemetry.javaagent.tooling.HelperInjector.transform(HelperInjector.java:174)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.doTransform(AgentBuilder.java:12822)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.transform(AgentBuilder.java:12759)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.access$1800(AgentBuilder.java:12468)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$Java9CapableVmDispatcher.run(AgentBuilder.java:13250)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$Java9CapableVmDispatcher.run(AgentBuilder.java:13180)
	at java.base/java.security.AccessController.doPrivileged(Unknown Source)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.doPrivileged(AgentBuilder.java)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer.transform(AgentBuilder.java:12702)
	at net.bytebuddy.agent.builder.AgentBuilder$Default$ExecutingTransformer$ByteBuddy$ModuleSupport.transform(Unknown Source)
	at java.instrument/sun.instrument.TransformerManager.transform(Unknown Source)
	at java.instrument/sun.instrument.InstrumentationImpl.transform(Unknown Source)
	at java.logging/java.util.logging.LogManager.ensureLogManagerInitialized(Unknown Source)
	at java.logging/java.util.logging.LogManager.getLogManager(Unknown Source)
	at org.slf4j.bridge.SLF4JBridgeHandler.getRootLogger(SLF4JBridgeHandler.java:132)
	at org.slf4j.bridge.SLF4JBridgeHandler.removeHandlersForRootLogger(SLF4JBridgeHandler.java:175)
	at play.api.libs.logback.LogbackLoggerConfigurator.configure(LogbackLoggerConfigurator.scala:91)
	at play.api.libs.logback.LogbackLoggerConfigurator.configure(LogbackLoggerConfigurator.scala:75)
	at play.api.inject.guice.GuiceApplicationBuilder.$anonfun$configureLoggerFactory$1(GuiceApplicationBuilder.scala:158)
	at scala.Option.map(Option.scala:242)
	at play.api.inject.guice.GuiceApplicationBuilder.configureLoggerFactory(GuiceApplicationBuilder.scala:157)
	at play.api.inject.guice.GuiceApplicationBuilder.applicationModule(GuiceApplicationBuilder.scala:116)
	at play.api.inject.guice.GuiceBuilder.injector(GuiceInjectorBuilder.scala:200)
	at play.api.inject.guice.GuiceApplicationBuilder.build(GuiceApplicationBuilder.scala:176)
	at play.api.inject.guice.GuiceApplicationLoader.load(GuiceApplicationLoader.scala:21)
	at play.core.server.ProdServerStart$.start(ProdServerStart.scala:52)
	at play.core.server.ProdServerStart$.main(ProdServerStart.scala:28)
	at play.core.server.ProdServerStart.main(ProdServerStart.scala)
Caused by: java.nio.file.FileSystemException: /tmp/opentelemetry-temp-jars6192078968140338460: Read-only file system
	at java.base/sun.nio.fs.UnixException.translateToIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixException.rethrowAsIOException(Unknown Source)
	at java.base/sun.nio.fs.UnixFileSystemProvider.createDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createDirectory(Unknown Source)
	at java.base/java.nio.file.TempFileHelper.create(Unknown Source)
	at java.base/java.nio.file.TempFileHelper.createTempDirectory(Unknown Source)
	at java.base/java.nio.file.Files.createTempDirectory(Unknown Source)
	at io.opentelemetry.javaagent.tooling.HelperInjector.createTempDir(HelperInjector.java:428)
	... 37 more
```

Is it required to have a writeable `tmp` folder for using the Java agent?

Note that the stacktrace seems to originate from logging libraries even though we don't use OTEL for logs (`OTEL_LOGS_EXPORTER=none`).

### Steps to reproduce

None yet, I can provide a MRE later if needed.

### Expected behavior

No error at startup

### Actual behavior

Errors at startup

### Javaagent or library instrumentation version

2.23.0

### Environment

**JDK**: 25.0.1
**OS**: Linux


### Additional context

_No response_

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Errors at startup in read-only filesystems environment #15666

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Errors at startup in read-only filesystems environment #15666

Description

Describe the bug

Steps to reproduce

Expected behavior

Actual behavior

Javaagent or library instrumentation version

Environment

Additional context

Tip

Metadata

Metadata

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Labels

Type

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Development

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