[#4077] improvement(docs): Fixed an incorrect Java example (#4079)

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### What changes were proposed in this pull request?

Fixed an incorrect Java example.

### Why are the changes needed?

Fix: #4077 

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

No testing required

Co-authored-by: rqyin <[email protected]>

docs/manage-metalake-using-gravitino.md

@@ -42,7 +42,7 @@ GravitinoAdminClient gravitinoAdminClient = GravitinoAdminClient
     .builder("http://localhost:8090")
     .build();
 
-GravitinoMetaLake newMetalake = gravitinoAdminClient.createMetalake(
+GravitinoMetalake newMetalake = gravitinoAdminClient.createMetalake(
     NameIdentifier.of("metalake"),
     "This is a new metalake",
     new HashMap<>());
@@ -79,7 +79,7 @@ curl -X GET -H "Accept: application/vnd.gravitino.v1+json" \
 
 ```java
 // ...
-GravitinoMetaLake loaded = gravitinoAdminClient.loadMetalake(
+GravitinoMetalake loaded = gravitinoAdminClient.loadMetalake(
     NameIdentifier.of("metalake"));
 // ...
 ```
@@ -123,7 +123,7 @@ curl -X PUT -H "Accept: application/vnd.gravitino.v1+json" \
 
 ```java
 // ...
-GravitinoMetaLake renamed = gravitinoAdminClient.alterMetalake(
+GravitinoMetalake renamed = gravitinoAdminClient.alterMetalake(
     NameIdentifier.of("new_metalake"),
     MetalakeChange.rename("new_metalake_renamed")
 );
@@ -213,7 +213,7 @@ curl -X GET -H "Accept: application/vnd.gravitino.v1+json" \
 
 ```java
 // ...
-GravitinoMetaLake[] allMetalakes = gravitinoAdminClient.listMetalakes();
+GravitinoMetalake[] allMetalakes = gravitinoAdminClient.listMetalakes();
 // ...
 ```
 

docs/manage-relational-metadata-using-gravitino.md

@@ -245,7 +245,7 @@ http://localhost:8090/api/metalakes/metalake/catalogs?details=true
 ```java
 // ...
 // Assuming you have just created a metalake named `metalake`
-Catalog[] catalogsInfos = gravitinoMetaLake.listCatalogsInfo(Namespace.ofCatalog("metalake"));
+Catalog[] catalogsInfos = gravitinoMetalake.listCatalogsInfo(Namespace.ofCatalog("metalake"));
 // ...
 ```