Error map
ArrayIndexOutOfBoundsException java.lang.ArrayIndexOutOfBoundsException: Index 5 out of bounds for length 5
Java · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (10). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (10)
Warning: Undefined array key / Undefined index
Your code reads an array key that doesn’t exist — common with `$_GET`, `$_POST` and decoded JSON.
TypeError: Reduce of empty array with no initial value
Array.reduce() ran on an empty array without an initial value.
java.lang.UnsupportedOperationException (List.of / Arrays.asList is immutable)
Code tried to modify an immutable or fixed-size collection.
java.lang.StringIndexOutOfBoundsException: begin 0, end 10, length 5
substring()/charAt() used an index outside the string.
[ERROR] Fatal error compiling: error: release version 17 not supported
The JDK running Maven is older than the Java version the project compiles for.
TypeError: Cannot read properties of undefined (reading 'length')
Code checked .length on something that is undefined — typically an array or string that hasn’t loaded.
Warning: Trying to access array offset on value of type null
Code used `$x['key']` where `$x` is null — usually a lookup or function that returned nothing.
IndexError: list index out of range
Code accessed a list position that doesn’t exist.
java.io.IOException: Stream closed
Code read or wrote a stream after it was closed — often by a try-with-resources block or a wrapper closing the underlying stream.
RangeError: Invalid array length
An array was created or resized with a negative, fractional or enormous length.
Two steps away (27)
TypeError: Cannot read properties of undefined (reading 'x')
You tried to access a property on a value that is `undefined` (or `null`) — usually data that hasn’t loaded yet or a wrong proper…
Warning: Cannot modify header information - headers already sent
You called `header()`, `setcookie()` or `session_start()` after output had already been sent to the browser.
KeyError: 'x'
You accessed a dictionary key that doesn’t exist.
AbortError: The user aborted a request. / signal is aborted without reason
A fetch was cancelled through an AbortController (or the browser cancelled it).
TypeError: Failed to execute 'json' on 'Response': body stream already read
A fetch Response body was consumed twice (e.g. calling .text() then .json()).
java.util.ConcurrentModificationException
A collection was modified while being iterated (even in a single thread).
java.lang.ClassCastException: class A cannot be cast to class B
An object was cast to a type it isn’t.
java.lang.ArithmeticException: / by zero
Integer division or modulo by zero.
java.nio.file.AccessDeniedException: /path
The OS denied a file operation to the Java process.
RangeError: Invalid string length
A string grew beyond the engine’s maximum length — usually runaway concatenation or huge JSON.stringify output.
TypeError: can only concatenate str (not "int") to str
You joined a string and a non-string with +.
Gradle: Unsupported class file major version / Android Gradle plugin requires Java 17 to run
The JDK running Gradle doesn’t match what the Gradle version or Android Gradle Plugin (AGP) supports.
java.lang.UnsupportedClassVersionError: class file version 61.0, this version of the Java Runtime only recognizes up to 55.0
Code compiled for a newer Java version is running on an older JVM.
ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
Build tools (Gradle, Maven, Android tools) can’t find a JDK.
TypeError: Cannot set properties of undefined (setting 'x')
Code assigned a property on a value that is undefined (or null).
TypeError: Cannot read properties of null (reading 'addEventListener')
document.querySelector/getElementById returned null, so the element doesn’t exist when the script runs.
TypeError: x is not iterable
for…of, spread or destructuring was used on something that isn’t an array/iterable.
TypeError: Cannot convert undefined or null to object
Object.keys/entries/assign was called with undefined or null.
Warning: Undefined variable $x
PHP read a variable that was never assigned in the current scope.
Warning: Undefined property: Class::$prop
Code read an object property that doesn’t exist on that object.
Warning: Each child in a list should have a unique "key" prop
When rendering a list with `.map()`, each element needs a stable, unique `key` so React can track items between renders.
AttributeError: 'X' object has no attribute 'y'
You accessed an attribute or method that doesn’t exist on that object type.
ConnectionRefusedError: [Errno 111] Connection refused
Nothing is listening on the host/port Python tried to connect to.
java.lang.ClassNotFoundException / NoClassDefFoundError
The JVM couldn’t find a class on the classpath at runtime.
Error: write EPIPE
Node wrote to a pipe or socket whose other end was already closed.
Error [ERR_STREAM_PREMATURE_CLOSE]: Premature close
A stream ended or was destroyed before it finished — often a client disconnect or upstream aborting a download.
Chrome: Aw, Snap! Something went wrong while displaying this webpage. Error code: STATUS_ACCESS_VIOLATION / SIGILL / Out of Memory
A Chrome tab crashed — out of memory, a faulty extension, a graphics/driver issue or a very heavy page.
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