# Quickstart Five minutes, two classpaths: the JDK (no setup at all) and a library pulled by its Maven coordinate. Every output below is real — it was produced by running the command when this page was built. ## 1. Ask about the JDK — zero setup The running JDK is always on the classpath, so this works straight after installing: ```console jdx-generated $ jdx members java.util.HashMap --limit 5 members of java.util.HashMap constructors declared on java.util.HashMap: constructor public HashMap() constructor public HashMap(int initialCapacity) constructor public HashMap(int initialCapacity, float loadFactor) constructor public HashMap(java.util.Map m) methods declared on java.util.HashMap: method public V compute(K key, java.util.function.BiFunction remappingFunction) + 7 from java.lang.Object (--from java.lang.Object to expand) 5 of 53 members shown (--limit 53 to see more) source: java.base (jrt) ``` The footer says what was cut and which `--limit` shows the rest. The `source:` line says where the answer came from. Now read one method — only that method: ```console jdx-generated $ jdx body 'java.util.HashMap#get(java.lang.Object)' java.util.HashMap#get(java.lang.Object) source: src.zip · java.base/java/util/HashMap.java:562-565 public V get(Object key) { Node e; return (e = getNode(key)) == null ? null : e.value; } next: jdx show java.util.HashMap ``` Always quote references in a shell: `#`, `(` and `$` are shell syntax. When there are no sources, jdx decompiles and marks the output `⚠ reconstructed`. ## 2. Ask about a library by Maven coordinate `--coord` resolves a library from your local Gradle and Maven caches; `--fetch` allows downloading it (and its `-sources.jar`) from Maven Central once: ```console jdx-generated $ jdx show com.google.gson.Gson --coord com.google.code.gson:gson:2.14.0 --fetch class com.google.gson.Gson public final class Gson extends java.lang.Object members: 2 constructors, 33 methods, 26 fields warning MULTI_RELEASE_VARIANT: multi-release gson-2.14.0.jar serves version-specific variants for this JDK (21) source: gson-2.14.0.jar (bytecode) next: jdx members com.google.gson.Gson --inherited ``` With sources available, `body` shows the real source with its file and line range: ```console jdx-generated $ jdx body 'com.google.gson.Gson#toJson(Object)' --coord com.google.code.gson:gson:2.14.0 com.google.gson.Gson#toJson(java.lang.Object) source: gson-2.14.0-sources.jar · com/google/gson/Gson.java:542-547 public String toJson(Object src) { if (src == null) { return toJson(JsonNull.INSTANCE); } return toJson(src, src.getClass()); } warning MULTI_RELEASE_VARIANT: multi-release gson-2.14.0.jar serves version-specific variants for this JDK (21) next: jdx show com.google.gson.Gson ``` ## 3. Let it refuse to guess `toJson` has several overloads. jdx will not pick one for you — it exits `2` and prints every candidate as a ready-to-paste reference: ```console jdx-generated $ jdx body 'com.google.gson.Gson#toJson' --coord com.google.code.gson:gson:2.14.0 ambiguous: 8 candidates for com.google.gson.Gson#toJson com.google.gson.Gson#toJson(com.google.gson.JsonElement) com.google.gson.Gson#toJson(com.google.gson.JsonElement, com.google.gson.stream.JsonWriter) com.google.gson.Gson#toJson(com.google.gson.JsonElement, java.lang.Appendable) com.google.gson.Gson#toJson(java.lang.Object) com.google.gson.Gson#toJson(java.lang.Object, java.lang.Appendable) com.google.gson.Gson#toJson(java.lang.Object, java.lang.reflect.Type) com.google.gson.Gson#toJson(java.lang.Object, java.lang.reflect.Type, com.google.gson.stream.JsonWriter) com.google.gson.Gson#toJson(java.lang.Object, java.lang.reflect.Type, java.lang.Appendable) hint: re-run with one of the refs above [exit 2] ``` ## 4. Find things and follow the graph ```console jdx-generated $ jdx search '*Json*Reader*' --coord com.google.code.gson:gson:2.14.0 search results for '*Json*Reader*' class com.google.gson.internal.JsonReaderInternalAccess gson-2.14.0.jar class com.google.gson.internal.bind.JsonTreeReader gson-2.14.0.jar class com.google.gson.internal.bind.JsonTreeReader$1 gson-2.14.0.jar class com.google.gson.internal.bind.JsonTreeReader$2 gson-2.14.0.jar class com.google.gson.stream.JsonReader gson-2.14.0.jar class com.google.gson.stream.JsonReader$1 gson-2.14.0.jar warning MULTI_RELEASE_VARIANT: multi-release gson-2.14.0.jar serves version-specific variants for this JDK (21) $ jdx hierarchy com.google.gson.JsonElement --coord com.google.code.gson:gson:2.14.0 hierarchy of 'com.google.gson.JsonElement' supertypes extends java.lang.Object java.base subtypes in workspace (4) class com.google.gson.JsonArray gson-2.14.0.jar class com.google.gson.JsonNull gson-2.14.0.jar class com.google.gson.JsonObject gson-2.14.0.jar class com.google.gson.JsonPrimitive gson-2.14.0.jar warning MULTI_RELEASE_VARIANT: multi-release gson-2.14.0.jar serves version-specific variants for this JDK (21) ``` ## 5. Name your classpath once Typing `--coord` on every command gets old. A named workspace stores the classpath; every command (and the MCP server, daemon and HTTP API) can reuse it: ```bash jdx ws create gson --coord com.google.code.gson:gson:2.14.0 jdx -w gson usages com.google.gson.TypeAdapter jdx ws use gson # make it the default for this machine ``` Inside a Gradle or Maven project you often need nothing at all: jdx discovers the project's sources and dependency jars from the working directory. See [Classpath \& workspaces](https://mohammadmd1383.github.io/jdx/docs/classpath/). ## 6. Hand it to your agent ```bash jdx setup --agent claude-code --scope project # or cursor, codex, opencode, copilot, antigravity, … ``` That is the whole integration — see [Use with AI agents](https://mohammadmd1383.github.io/jdx/docs/ai-agents/). ## Where next - [Symbol references](https://mohammadmd1383.github.io/jdx/docs/symbol-references/) — every way to name a class or member. - [Reading code](https://mohammadmd1383.github.io/jdx/docs/reading-code/) and [Usages, hierarchy \& calls](https://mohammadmd1383.github.io/jdx/docs/navigating-code/). - The [command catalogue](https://mohammadmd1383.github.io/jdx/docs/reference/).