fix(java): Stop using Streams to render params (#459)

The Java cod egenerated by `jsii-pacmak` used to use `Stream`
concatenations to render parameters into an `Object` array when passing
to the low-level `jsii` engine. In the majority of cases this worked
fine, however in casesw where the last argument was an `enum`, this
caused `javac` type inferrence to impose bounds on the `Stream`'s item
type that could not be met by non-`enum` types.

Additionally, as this code demonstrates, the `Stream`-based code was
unnecessarily complicated as it is possible to initialize an array
literal in place, by using less code, which also reads simpler, and
incurs less memory churn. It's a win all over the board 🎉

Author: RomainMuller

packages/jsii-pacmak/lib/targets/java.ts

@@ -987,17 +987,9 @@ class JavaGenerator extends Generator {
 
     private renderMethodCallArguments(method: spec.Method) {
         if (!method.parameters || method.parameters.length === 0) { return ''; }
-        let paramStream: string = '';
-        for (const param of method.parameters) {
-            const paramValue = isNullable(param) ? param.name : `java.util.Objects.requireNonNull(${param.name}, "${param.name} is required")`;
-            const thisParam = `${param.variadic ? 'java.util.Arrays.stream' : 'java.util.stream.Stream.of'}(${paramValue})`;
-            if (paramStream === '') {
-                paramStream = thisParam;
-            } else {
-                paramStream = `java.util.stream.Stream.concat(${paramStream}, ${thisParam})`;
-            }
-        }
-        return `, ${paramStream}.toArray()`;
+        const values = method.parameters.map(param =>
+            isNullable(param) ? param.name : `java.util.Objects.requireNonNull(${param.name}, "${param.name} is required")`);
+        return `, new Object[] { ${values.join(', ')} }`;
     }
 
     private renderMethodCall(cls: spec.TypeReference, method: spec.Method, async: boolean) {

packages/jsii-pacmak/test/expected.jsii-calc-lib/java/src/main/java/software/amazon/jsii/tests/calculator/lib/Number.java

@@ -16,7 +16,7 @@ protected Number(final software.amazon.jsii.JsiiObject.InitializationMode mode)
      */
     public Number(final java.lang.Number value) {
         super(software.amazon.jsii.JsiiObject.InitializationMode.Jsii);
-        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, java.util.stream.Stream.of(java.util.Objects.requireNonNull(value, "value is required")).toArray());
+        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, new Object[] { java.util.Objects.requireNonNull(value, "value is required") });
     }
 
     /**

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/AbstractClass.java

@@ -42,7 +42,7 @@ public java.lang.String getAbstractProperty() {
 
         @Override
         public java.lang.String abstractMethod(final java.lang.String name) {
-            return this.jsiiCall("abstractMethod", java.lang.String.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(name, "name is required")).toArray());
+            return this.jsiiCall("abstractMethod", java.lang.String.class, new Object[] { java.util.Objects.requireNonNull(name, "name is required") });
         }
     }
 }

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/Add.java

@@ -17,7 +17,7 @@ protected Add(final software.amazon.jsii.JsiiObject.InitializationMode mode) {
      */
     public Add(final software.amazon.jsii.tests.calculator.lib.Value lhs, final software.amazon.jsii.tests.calculator.lib.Value rhs) {
         super(software.amazon.jsii.JsiiObject.InitializationMode.Jsii);
-        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, java.util.stream.Stream.concat(java.util.stream.Stream.of(java.util.Objects.requireNonNull(lhs, "lhs is required")), java.util.stream.Stream.of(java.util.Objects.requireNonNull(rhs, "rhs is required"))).toArray());
+        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, new Object[] { java.util.Objects.requireNonNull(lhs, "lhs is required"), java.util.Objects.requireNonNull(rhs, "rhs is required") });
     }
 
     /**

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/AllTypes.java

@@ -18,7 +18,7 @@ public AllTypes() {
     }
 
     public void anyIn(@javax.annotation.Nullable final java.lang.Object inp) {
-        this.jsiiCall("anyIn", Void.class, java.util.stream.Stream.of(inp).toArray());
+        this.jsiiCall("anyIn", Void.class, new Object[] { inp });
     }
 
     @javax.annotation.Nullable
@@ -27,7 +27,7 @@ public java.lang.Object anyOut() {
     }
 
     public software.amazon.jsii.tests.calculator.StringEnum enumMethod(final software.amazon.jsii.tests.calculator.StringEnum value) {
-        return this.jsiiCall("enumMethod", software.amazon.jsii.tests.calculator.StringEnum.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(value, "value is required")).toArray());
+        return this.jsiiCall("enumMethod", software.amazon.jsii.tests.calculator.StringEnum.class, new Object[] { java.util.Objects.requireNonNull(value, "value is required") });
     }
 
     public java.lang.Number getEnumPropertyValue() {

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/AllowedMethodNames.java

@@ -12,24 +12,24 @@ public AllowedMethodNames() {
     }
 
     public void getBar(final java.lang.String _p1, final java.lang.Number _p2) {
-        this.jsiiCall("getBar", Void.class, java.util.stream.Stream.concat(java.util.stream.Stream.of(java.util.Objects.requireNonNull(_p1, "_p1 is required")), java.util.stream.Stream.of(java.util.Objects.requireNonNull(_p2, "_p2 is required"))).toArray());
+        this.jsiiCall("getBar", Void.class, new Object[] { java.util.Objects.requireNonNull(_p1, "_p1 is required"), java.util.Objects.requireNonNull(_p2, "_p2 is required") });
     }
 
     /**
      * getXxx() is not allowed (see negatives), but getXxx(a, ...) is okay.
      */
     public java.lang.String getFoo(final java.lang.String withParam) {
-        return this.jsiiCall("getFoo", java.lang.String.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(withParam, "withParam is required")).toArray());
+        return this.jsiiCall("getFoo", java.lang.String.class, new Object[] { java.util.Objects.requireNonNull(withParam, "withParam is required") });
     }
 
     public void setBar(final java.lang.String _x, final java.lang.Number _y, final java.lang.Boolean _z) {
-        this.jsiiCall("setBar", Void.class, java.util.stream.Stream.concat(java.util.stream.Stream.concat(java.util.stream.Stream.of(java.util.Objects.requireNonNull(_x, "_x is required")), java.util.stream.Stream.of(java.util.Objects.requireNonNull(_y, "_y is required"))), java.util.stream.Stream.of(java.util.Objects.requireNonNull(_z, "_z is required"))).toArray());
+        this.jsiiCall("setBar", Void.class, new Object[] { java.util.Objects.requireNonNull(_x, "_x is required"), java.util.Objects.requireNonNull(_y, "_y is required"), java.util.Objects.requireNonNull(_z, "_z is required") });
     }
 
     /**
      * setFoo(x) is not allowed (see negatives), but setXxx(a, b, ...) is okay.
      */
     public void setFoo(final java.lang.String _x, final java.lang.Number _y) {
-        this.jsiiCall("setFoo", Void.class, java.util.stream.Stream.concat(java.util.stream.Stream.of(java.util.Objects.requireNonNull(_x, "_x is required")), java.util.stream.Stream.of(java.util.Objects.requireNonNull(_y, "_y is required"))).toArray());
+        this.jsiiCall("setFoo", Void.class, new Object[] { java.util.Objects.requireNonNull(_x, "_x is required"), java.util.Objects.requireNonNull(_y, "_y is required") });
     }
 }

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/AsyncVirtualMethods.java

@@ -38,7 +38,7 @@ public java.lang.Number dontOverrideMe() {
     }
 
     public java.lang.Number overrideMe(final java.lang.Number mult) {
-        return this.jsiiAsyncCall("overrideMe", java.lang.Number.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(mult, "mult is required")).toArray());
+        return this.jsiiAsyncCall("overrideMe", java.lang.Number.class, new Object[] { java.util.Objects.requireNonNull(mult, "mult is required") });
     }
 
     public java.lang.Number overrideMeToo() {

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/BinaryOperation.java

@@ -17,7 +17,7 @@ protected BinaryOperation(final software.amazon.jsii.JsiiObject.InitializationMo
      */
     public BinaryOperation(final software.amazon.jsii.tests.calculator.lib.Value lhs, final software.amazon.jsii.tests.calculator.lib.Value rhs) {
         super(software.amazon.jsii.JsiiObject.InitializationMode.Jsii);
-        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, java.util.stream.Stream.concat(java.util.stream.Stream.of(java.util.Objects.requireNonNull(lhs, "lhs is required")), java.util.stream.Stream.of(java.util.Objects.requireNonNull(rhs, "rhs is required"))).toArray());
+        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, new Object[] { java.util.Objects.requireNonNull(lhs, "lhs is required"), java.util.Objects.requireNonNull(rhs, "rhs is required") });
     }
 
     /**

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/Calculator.java

@@ -16,7 +16,7 @@ protected Calculator(final software.amazon.jsii.JsiiObject.InitializationMode mo
      */
     public Calculator(@javax.annotation.Nullable final software.amazon.jsii.tests.calculator.CalculatorProps props) {
         super(software.amazon.jsii.JsiiObject.InitializationMode.Jsii);
-        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, java.util.stream.Stream.of(props).toArray());
+        software.amazon.jsii.JsiiEngine.getInstance().createNewObject(this, new Object[] { props });
     }
     /**
      * Creates a Calculator object.
@@ -30,14 +30,14 @@ public Calculator() {
      * Adds a number to the current value.
      */
     public void add(final java.lang.Number value) {
-        this.jsiiCall("add", Void.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(value, "value is required")).toArray());
+        this.jsiiCall("add", Void.class, new Object[] { java.util.Objects.requireNonNull(value, "value is required") });
     }
 
     /**
      * Multiplies the current value by a number.
      */
     public void mul(final java.lang.Number value) {
-        this.jsiiCall("mul", Void.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(value, "value is required")).toArray());
+        this.jsiiCall("mul", Void.class, new Object[] { java.util.Objects.requireNonNull(value, "value is required") });
     }
 
     /**
@@ -51,7 +51,7 @@ public void neg() {
      * Raises the current value by a power.
      */
     public void pow(final java.lang.Number value) {
-        this.jsiiCall("pow", Void.class, java.util.stream.Stream.of(java.util.Objects.requireNonNull(value, "value is required")).toArray());
+        this.jsiiCall("pow", Void.class, new Object[] { java.util.Objects.requireNonNull(value, "value is required") });
     }
 
     /**

packages/jsii-pacmak/test/expected.jsii-calc/java/src/main/java/software/amazon/jsii/tests/calculator/ClassWithPrivateConstructorAndAutomaticProperties.java

@@ -11,7 +11,7 @@ protected ClassWithPrivateConstructorAndAutomaticProperties(final software.amazo
     }
 
     public static software.amazon.jsii.tests.calculator.ClassWithPrivateConstructorAndAutomaticProperties create(final java.lang.String readOnlyString, final java.lang.String readWriteString) {
-        return software.amazon.jsii.JsiiObject.jsiiStaticCall(software.amazon.jsii.tests.calculator.ClassWithPrivateConstructorAndAutomaticProperties.class, "create", software.amazon.jsii.tests.calculator.ClassWithPrivateConstructorAndAutomaticProperties.class, java.util.stream.Stream.concat(java.util.stream.Stream.of(java.util.Objects.requireNonNull(readOnlyString, "readOnlyString is required")), java.util.stream.Stream.of(java.util.Objects.requireNonNull(readWriteString, "readWriteString is required"))).toArray());
+        return software.amazon.jsii.JsiiObject.jsiiStaticCall(software.amazon.jsii.tests.calculator.ClassWithPrivateConstructorAndAutomaticProperties.class, "create", software.amazon.jsii.tests.calculator.ClassWithPrivateConstructorAndAutomaticProperties.class, new Object[] { java.util.Objects.requireNonNull(readOnlyString, "readOnlyString is required"), java.util.Objects.requireNonNull(readWriteString, "readWriteString is required") });
     }
 
     @Override